Engine dies when decelerating

I have a 2000 "Chevy" Metro with a 1.0L 3 cylinder engine. Last week, while driving my 50 mile comute home, it just stopped. The engine would turn over but not run. Once the car sat for 30 minutes or so, it would start fine and run for awhile and stop occasionally. I replaced the distrubutor cap and the rotor on the advice of a friend, but this did not help. I remembered a similar problem that I had in another vehicle a few years back and replaced the Electronic Control Module. Problem solved or so I thought. This morning, after 5 days of running perfectly, it died again. Sometimes it will crank right back up and sometimes it just has to sit there for a few minutes till it will. I picked up another ECM thinking I might have gotten a faulty one and sure enough, it cranked right back up and ran....for 4 miles then died as I was slowing down. I got it to start again and continued this until I made it to work. If i managed to keep my rpms above idle, the motor would not die, but if I let it drop down to idle it was game over.

Does anyone have an idea of what this problem could be? I really could use the help.

You know I had a 95 escort that was only about 6 years old at the time and it did the same thing.
I replaced the fuel filter, and it was plugged up sooo bad I could hardly blow through it. I blew it out with an air hose and there was a ton of crap in there!
I'd check yours if you've never changed it.

I will check it, but i was thinking that if it is running fine at the higher rpms like driving down the highway, if it was clogged, i would be having problems then too. Shouldnt it act like it was starving for fuel.

A burned valve will cause very bad idle or low RPM performance but might not be as noticeable at high speeds. Check the compression on this engine and go from there.

If the compression checks out, try a new set of plugs (NGK) and good set of wires next.

I agree with Metro_Roy.

A fuel filter was my problem. But I'd definitely do a compression test.
There cheap to buy about 20 bucks.

OK, still haven't done the compression test nor checked the fuel filter since it is in the fuel tank. Trying to weed out any other problems before I have to drop the tank. But just to keep you guys in the loop, I found the pcv valve totally blocked -replaced it-. Now it still dies when I let off of the gas, but it will restart right away if i turn the ignition all the way off and back on to let the fuel pump build pressure back up. It won't restart unless I do this. Starting to look like I am going to have to drop the tank for the fuel pump and filter eh? Also brought it by a real mechanic to take a look at it and he said to check my throttle body motor assembly -not sure if that name is correct- which I did and it is clean as can be on the inside. Oh yeah the metro will not die if it is sitting still in the driveway, rev it as much as you want, but just on the road while driving.

The fuel filter is not in the tank. It is located on the frame back by the drivers side rear wheel. Follow the gaslines back from the engine and you'll see it before they get to the gas tank.

Ah. I haven't looked yet, I was just assuming it was since I can't seem to find a replacement for the fuel filter other than the one located on the pump in the tank. But I will look for it this afternoon after I get off of work.

You're right, the only fuel "filter" you have is a cotton sock over the pickup inside the tank. If I were to go to all that trouble, I'd replace the pump too.

Ugh, yep confirmed. since this is a 2000 model, the fuel "filter" is in the tank. I will probably bring the car to a mechanic in 2 days when I can since I just wont have the time nor the equipment to raise my car to get to the fuel take. I really hope this solves the problem.

You should have someone test the fuel pressure before going to the expense of having the tank dropped to change something that rarely causes trouble.

Doh, I hate it when I give bum advice. I went to the www.advanceautoparts.com (http://www.advanceautoparts.com) before I posted the message, and they listed the same fuel filter as for my 95, so I ASSUMED, the 2000 is the same as a 95.

I have a 2000 "Chevy" Metro with a 1.0L 3 cylinder engine. Last week, while driving my 50 mile comute home, it just stopped. The engine would turn over but not run. Once the car sat for 30 minutes or so, it would start fine and run for awhile and stop occasionally. I replaced the distrubutor cap and the rotor on the advice of a friend, but this did not help. I remembered a similar problem that I had in another vehicle a few years back and replaced the Electronic Control Module. Problem solved or so I thought. This morning, after 5 days of running perfectly, it died again. Sometimes it will crank right back up and sometimes it just has to sit there for a few minutes till it will. I picked up another ECM thinking I might have gotten a faulty one and sure enough, it cranked right back up and ran....for 4 miles then died as I was slowing down. I got it to start again and continued this until I made it to work. If i managed to keep my rpms above idle, the motor would not die, but if I let it drop down to idle it was game over.

Does anyone have an idea of what this problem could be? I really could use the help.
It is most likely 1 of 3 things that are wrong, Fuel pump relay or, the ignition relay is bad, when it cools down it works again. To test this yourself, most likely the relay box is with the fuse box under the hood. Switch places with the 2 relays; they should both be the same. A bad connection on the ignition switch can do this to you also. If you have any accessories attached to that ignition that were not factory installed, like an amplifier for your stereo, or as a back yard mechanic will connect the coolant fan to the ignition load to by pass a problem that is beyond his abilities to fix properly, this will cause the ignition relay and or ignition switch to over load and burn out in turn causing your symptoms. Also it could be many more things MAP sensor would be up high on the list also. I hope that this helps you!

Well, yesterday, I went searching for a way to test the fuel pressure. Gonna have to rig something up since my local parts store doesnt have a set up for that. I also purchased a ignition coil and swapped out the ECM again because someone told me it could be my coil frying the ecm....still same issues. I haven't tried the relays yet, but I will do that tonight when I get home. Gonna cross my fingers when I do. Thanks for the help guys and I will keep posting with all the findings. I just gotta fix this tough little car. It may be ugly and beat up, but I love it.

My first checks would be, a vacuum leak, as in broken or cracked hose, or throttle body and intake gaskets, or anything that is on the intake. It does'nt take much of a vacuum leak to cause this. My next check would be EGR valve. If its stuck open it can cause this. I doubt very much that ignition is the culprit, except for one thing. There have been posts of some guys saying the coil wire works its way out of the coil at times even though it appears to still be connected. Hope its that easy for you. Anyway good luck.

My first checks would be, a vacuum leak, as in broken or cracked hose, or throttle body and intake gaskets, or anything that is on the intake. It does'nt take much of a vacuum leak to cause this. My next check would be EGR valve. If its stuck open it can cause this. I doubt very much that ignition is the culprit, except for one thing. There have been posts of some guys saying the coil wire works its way out of the coil at times even though it appears to still be connected. Hope its that easy for you. Anyway good luck.
True the EGR could be sticking oden at times. Maby we will see!

I haven't seen any cracked hoses or any obvious leaks. I swapped out the relays as suggested but that didn't do anything. I haven't checked the egr valve yet. Not sure exactly where it is, but I imagine its posted somewhere around here. Time to do some forum diving.

If you can get it running again, pull the vacuum hose off the EGR valve and plug it with a small bolt (the hose ). If your not sure what the EGR looks like, look it up on autozone.com. If problem disappears, you found the problem. (EGR sticking open)

Okay, found and "checked" the EGR last night per Chilton's manual. Started the car, let it get to normal running temperature and could see the EGR moving slightly. I pushe the diaphram up by hand and the car died instantly. Guess its working properly. I will be dropping the fuel tank tonight and start to replace the fuel filter and pump.

Okay, found and "checked" the EGR last night per Chilton's manual. Started the car, let it get to normal running temperature and could see the EGR moving slightly. I pushe the diaphram up by hand and the car died instantly. Guess its working properly. I will be dropping the fuel tank tonight and start to replace the fuel filter and pump.
What the other guy was saying about the EGR is good input! But now that you have tested it and see that it is working properly, realize that at times if it were to hang open; At an idle it would make the engine stall, and hard to restart. I still think that you have a bad relay. But knowing the nature of electronics it could just as easily be a bad fuel pump that could be overloading the relay. An ignition coil once that it heats up can brake down and not start your car until it cools down. It can be tested with an ohm meter; but you would need to know the specs. Most any of your integrated electronic ignition components have this same nature, including the ECM, which I think you have replaced.
If you have any questions I will help for free.
You can call me at my garage if you like. I have all the data at my finger tips there. I will give you my email address: [email protected] ([email protected]) after you email me I will email back to you my name and phone number. I just don’t want to post this info, it could hang around for ever and wake me up at nights. So call at normal working Hrs. Eastern Time Zone, Dennybam

I wasn't clear about the EGR test. After you plug the hose you have to drive it to see if it was sticking open. If you have no problem, then it could be sticky EGR. If it stalls then you can rule out EGR.

Still have my fingers crossed, but I think the problem is fixed. I finally got the fuel tank off and replace the fuel pump and filter. I have driven it about 80 miles since and it died on me 2 times about 8 miles into the trip home from my father-in-laws house where I was working on it. I am hoping that was an air bubble in the line or a bit of trash broke loose in the line,or maybe just the ecm learning the new pump. It didn't die for the rest of the 30 mile trip home nor did it die this morning on the way to work which is 49 miles. If it acts up again, I will check out the EGR since it is one of the few things left that I haven't looked at.

The car seems to have a higher idle now than before and it seems to rev up and down while idleing now, but other than that, seems fine.

2000 Metro
178,000 miles
38-42 mpg
3 cylinder

Oh and just to brag about how tough these cars are, I rolled it over in a ditch at 140k miles to avoid an idiot 18 wheeler that decided to turn and take up the whole hwy. Two complete roll overs. I lost the pasenger side mirror, messed up the body work and shattered the pasenger side of the windshield. I landed right side up. Had a tow truck pull me out of the ditch, which was muddy. Put the radiator back in its posts and hooked the battery back up. I then drove to work. Ran fine until this current problem. Tough car :-)

Gonna try to get as many miles out of it as I can.

Thanks for all your suggestions and help everyone, I will be keeping an eye on the forums here to lend my 2 cents for what its worth.

Ugh...well, its acting up again. ran fine for a few days now doing the same thing again except it has a fluctuating idle now. well, time to check the EGR and timing belt.

Well, here is an update. Still have the problem of stalling when I let off the gas. I have replaced the EGR valve, MAP sensor, fuel pump, fuel filter, and fuel pressure regulator. Still having the same problem. Tested the compression, which was 170, 173, 165. Dennybam said these were a bit low, but acceptable. Figured out my fluctuating idle....silly me forgot to tighten a bolt all the way...duh.

But all said and done, still have the same problem.

Dennybam also suggested that I look at the idle air control valve. Well, I can't seem to find it. My Chilton's manual shows it in the spot where the throttle position sensor is. Any ideas O' gooroos of the Metro?

I don't see in this thread where you've replaced plugs (use NGK) wires or any other ignition parts. Have you checked the timing? Have you checked for codes with an OBDII reader?

Yes, I have replaced the plugs, distributor cap, rotor, ignition coil, and the ecm on it. But I have not replaced the plug wires. The check engine light has never come on. It does come on with the light check on initial start up though so it is not burnt out. I have not checked the timing, nor do I know how. I was told that if my timing was sliping or off, it would run horrible or not even start. It starts and runs and sounds great, it just dies after I have had the rpms up and let off the gas to shift. If I shift and give it gas fast enough, it wont stall. It seems to only occur when it tries to drop down to the idle position. This is why Dennybam suggested that the idle air valve might be sticking -and I cant find it-.

So, when you first start it up cold, will it sit there and idle fine? When you first take off with the engine still cold (open loop) does it stall when taking your foot off the gas or does the car have to be at temperature (closed loop) for it to mis-behave?

This is a question for metro roy, I have a 91 geo prism and I'm trying to locate the fuel filter, any ideas? Mine tries to die out when i slow down or idle. I'm new to forums and not sure how to post a question, so that is why i am asking here. Thanks.

FemaleDriver:

The prism is an entirely different car than the Metros talked about on this forum. I happen to have a haynes manual on a prism and I'll look up your question when I get home and try to answer later. Someone else here might be able to answer you sooner.

The metro seems to run fine when it is still cold meaning not up to running temperature and only stalls when it is at normal operating temperature. I can start it up and it idles just fine. And just to throw y'all a curve, it does not always die when I let off the gas at normal temp. If I slowly let up on the pedal...very slowly....sometimes it won't stall.

Have you replaced the oxygen sensor? If not, try that.

Thanks metro roy, I appreciate the help. This is just getting more confusing. I just found out that the guy I bought the prism from put a 91 toyota corrolla motor in it, and I don't know if that would make a differance as far as the fuel filter. What do you think?

Femaledriver:

A prizm has a Toyota engine, and is basically the same car as a corolla. See:

http://en.wikipedia.org/wiki/Geo/Chevrolet_Prizm

Are the parts/part # the same? I looked at one at Napa and I can't see anything that looks like it. Found something that looks similar but the brackets are different. Thanks.

Hey thanks metro roy, i found it but doesn't look like anything i can easily get to. Its going to a mechanic. Thanks again.

How do you test the O2 sensor? The one that goes in front of the cat conv is $75 and the one that goes behind it is $200...I really dont want to purchase these unless I know they are bad. Thats alot of money.

Lilblu:

Someone else here is going to have to help you on that one. The Geo's I've worked on and own have been older (95 & earlier) with OBDI and only one O2 sensor. On my car it is much cheaper. I suggest the O2 sensor because once the engine is up to operating temperature, the ECM looks at the O2 sensor and controls the pulse width of the fuel injector, making it richer or leaner depending on how much unburned oxygen is in the exhaust. Since your car seems to run okay before it goes into closed loop, I thought this might be a cheap fix. I THINK (don't know for sure) that the upstream one is the that effects fuel injection and the one after the converter just verifies that the cat is working. See: http://en.wikipedia.org/wiki/Oxygen_sensor
There is a way to test the O2 sensor but I don't know what the voltage reading would be for your newer car. Can anyone else help Lilblu here?

Lilblu:

Here's another Idea. Since you are going to keep this great mileage vehicle for a Long time, invest in a shop service manual. It will tell you how to check out the sensors. I checked at http://www.books4cars.com . They have one for your car for $80.

ECT anybody?

Get a scantool on that thing and verify the PCM is seeing coolant temps of 190-205°F when the needle is centered.

-MechanicMatt

Well, been a couple of weeks since I updated this....Still having the same issues. Brought it to a local "mechanic" shop. They couldn't find the problem. They told me that they could not get the car to stall in their shop. Only when they drove it! so after having it for a week the gave up and told me they couldnt find the problem. At least they did not charge me anything. On a suggestion of a friend, I purchased some Sea Foam cleaner and poured some in the fuel tank, throttle body and oil as per instrustions. drove it for 15 miles or so and parked it. I went on vacation for a week and when I came back, the car ran fine for 200 miles -2 days of work commute- then this morning started acting up again. Is it possible that the fuel injector is going bad?

Calling all experts:

I've read on another forum that a catalytic convertor plugging can have symptoms like lilblue describes. what are your thoughts and experience with plugging cats?

Hey Roy, I think you're onto something here. A cat in the process of clogging will indeed have these kinds of symptoms.

Cold runs fine, heats up, the monolith expands and closes off one too many holes and presto you can't get the spent fuel out of the cylinders fast enough to burn the fresh stuff.

LilBlu: If you don't have a vacuum gauge get one. Then disconnect the brake booster vacuum hose from the brake booster and plug the vacuum gauge into that puppy after letting the engine idle to operating temperature. Record a vacuum reading at 1000rpms, then log another reading at ~2500rpms. If your 2.5k reading is 3in.hg. or more lower than your 1k reading, your exhaust may be clogged.

If so, repeat this test with the exhaust system disconnected from the exhaust manifold via the two sprung 14mm hex bolts. If you don't observe the same loss in vacuum, than Roy found your problem.

-MechanicMatt

I will pick up a vacuum tester this afternoon. I dont have a tach on the car so i will have to guess at the rpms. Lets hope this works.....now that I think about it, a couple of months ago, the exhaust pipe snapped off of the front of the cat and I drove like that for a few days till I had the time to get it rewelded.

Well, tested the vacuum like you said and that wasnt the problem. even with the cat. unhhoked from the maniflod, pressures stayed about the same and car died.

I did however move the TPS that someone mentioned earlier. didnt know how to test it so i just changed its position to see what would happen. The searching idle disappered and running smooth. Bout to go road test it and see what happens.

Wel the TPS was not the problem. I Stopped by a junk yard and bought a whole throttle body with TPS and injector for $40 and cleaned it up. I first tried the TPS. still had the same issue. Then I swapped out the fuel injector and seems to be fixed. Hasn't cut out on me in 3 days. I did get lucky and actually have someone with me when it cut out and wouldnt restart so I got to find out that there was spark but no fuel coming out of the injector. Gonna drive it some more and see what happens. Still has a very low idle when I first crank it up. Maybe the idle air is stuck open on the throttle body. gonna replace that on my next day off.


Edit:
Yep, After 500 miles, I can definitely say it was the fuel injector causing all the troubles.