1996 LSS surging and stalling....

I have a '96 non-supercharged LSS. I recently bought it from an old lady (purchased about a month ago). It has 75k orig miles on it. Didn't have any mantainance record so I have just been trying to replace everything that I can think of just for the heck of it.
Problem is while in traffic seems to happen the most.... when I am kinda stopping and going the RPM's will rise to 1500-1800 and the car will want to drive while I am pressing down the brake. If I bring it to a complete stop the RPMs will come down after a few secs. It will stall sometimes. Sometimes like this morning I had only made it about 3 miles from home and on residential street it stalled. It will always start right back up.
things I have done so far: changed spark plug wires (was told the plugs were good), air filter, fuel filter, new starter, new tensioner pulley w/ new bypass tubes.
I wish I knew how to post a pic cuz it looks like someone may have put the wrong Mass airflow sensor on it.
Any info would help. (it doesn't die everytime I drive, kinda intermitten)
thanks

What are the numbers on the MAF. Posting pics is easy, 1st you need to setup an account with an online host. Most use www.photobucket.com (http://www.photobucket.com). It's free BTW.

What are the numbers on the MAF. Posting pics is easy, 1st you need to setup an account with an online host. Most use www.photobucket.com (http://www.photobucket.com). It's free BTW.

Nevermind. I am an idiot. I was looking at the EGR and thinking it was the MAF sensor. But would a bad MAF sensor be causing the problems I am having?

It's possible that the MAF is the problem. You really need a scanner to check it properly but you can try unplugging it & see if it runs better. Vacuum leaks are a strong possiblity as well as the PCV valve. Try removing the oil filler cap & cover the opening with the palm of your hand. If you feel a strong vacuum then replace the PCV valve & repeat the test. Engine needs to be running while testing.

I had a similar problem with a '94 I have. Would idle high (sometimes shoot up to 1500-1800rpm) at idle, and would also stall when I let off the gas while driving. Started back up every time.

Replaced the IAC (Idle Air Control) first, but that didn't fix it. Unplugged the TPS (Throttle Position Sensor) and the car ran fine. Replaced the TPS and haven't had the problem since.

Not saying it's your problem, but thought it worth mentioning. Good luck.

It's possible that the MAF is the problem. You really need a scanner to check it properly but you can try unplugging it & see if it runs better. Vacuum leaks are a strong possiblity as well as the PCV valve. Try removing the oil filler cap & cover the opening with the palm of your hand. If you feel a strong vacuum then replace the PCV valve & repeat the test. Engine needs to be running while testing.
well yesterday I changed the PCV valve and it really didn't seem to change anything. this morning was like a carbon copy of yesterday. Car died a couple miles from home. started right back up. then after about 20 miles of commuting and entering stop and go traffic the surging starts and died again. I took the MAF off yesterday and shot it with compressed air hoping that would do something like clean it. This car just started the dying in the morning this week. I have have had it for at least a couple week prior to this happening. Over the weekend I changed the fuel and air filter and change the spark plug wires. I dont think any of that would cause these current probs ... would they?

I had a similar problem with a '94 I have. Would idle high (sometimes shoot up to 1500-1800rpm) at idle, and would also stall when I let off the gas while driving. Started back up every time.

Replaced the IAC (Idle Air Control) first, but that didn't fix it. Unplugged the TPS (Throttle Position Sensor) and the car ran fine. Replaced the TPS and haven't had the problem since.

Not saying it's your problem, but thought it worth mentioning. Good luck.
Thanks man. that sounds pretty similar to my problem. I will check this out also.
One thing i forgot to mention I believe this car was sitting around for a while prior to me buying it. Reason I changed the wires was it looked like an animal had been chewing on them. When I first remove the sight guard (?) there was all this stuff underneath it like a nest or something. LOL

Did you try unplugging the MAF?
Double check that none of the spark plug wires got mixed up. Also make sure none of the wires are within a couple inches of the O2 sensor & wiring.

Examine all the vacuum lines & wiring for any damage from your furry friend.

Did you try unplugging the MAF?
Double check that none of the spark plug wires got mixed up. Also make sure none of the wires are within a couple inches of the O2 sensor & wiring.

Examine all the vacuum lines & wiring for any damage from your furry friend.

No. didn't unplug the MAF. Can I unplug it and just drive around? Because it will usually start acting like this after driving for a little and will not surge if just idling in my driveway.
Actually, the wires may be close to that O2 sensor. I will check again.

BTW.... where do you add power steering fluid??? I was doing that stuff to it yesterday and it occured to me .. "where the hell it the power steering resevior?"

Yeah, it's ok to drive around with it unplugged. Some people report back that it ran like crap with the MAF unplugged & others notice an immediate improvement. :runaround:

Yeah, it's ok to drive around with it unplugged. Some people report back that it ran like crap with the MAF unplugged & others notice an immediate improvement. :runaround:
well I unplugged it and seem to run worse. Idle didn't seem to know where to be. When plugged up it seemed to run better. Does this eliminate the MAF as the problem?
Also , now my check engine light is on.
I drove to work today and it was basically the same as it had been.
Yesterday I view the firing sequence on Autozones website. Weird thing is the numbers on the cylinders seem to be the same but on the coil thing my numbers are in different order. the part in my car has them labeled and they are in different order as the diagram from autozone. com. ?????
WTF... I went to lunch and my car wouldn't start. No cranking or anything but all the lights were on. Came back from lunch(walking) went to car and it started right up??????IDK

Below is a pic that shows the proper coil locations & the numbering for the cylinders. The code you have is probably from having the MAF unplugged, that should clear in a few days. We really can't eliminate anything until it's fixed. Can you get a video of the engine idling?



http://i26.photobucket.com/albums/c120/BCGearhead/96-99%20Series%202%20L67/MAF.jpg (http://s26.photobucket.com/albums/c120/BCGearhead/96-99%20Series%202%20L67/?action=view&current=MAF.jpg)

Below is a pic that shows the proper coil locations & the numbering for the cylinders. The code you have is probably from having the MAF unplugged, that should clear in a few days. We really can't eliminate anything until it's fixed. Can you get a video of the engine idling?


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My plugs are just like the pic. Well I went and bought a new throttle position sensor. I replaced it and it seemed to run good. But wouldn't really know til the commute this morning. Well it didn't surge or die once on my way to work which is about 32-34miles. So I was all happy because I think i fixed the prob. well on my lunch break went to the bank and the RPM's started surging really high like 2500 and they didnt seem to want to come down. I had to turn the car off and restart it. drove back to work fine.
any ideas???
now that i have read about other cars surging ,i think it happens mostly on inclines. Does that usually indicate a certain thing?

i guess i spoke too soon. this morning it was up to its old tricks again, although the TPS seemed to help a bit. I died again after a couple miles away from the house and then it surged and stalled after about 25 miles. I wasn't on an incline though.
????/:banghead:

When does it stall? Just when coming to a stop, while cruising or both?

We also need to know if you're losing any coolant or seeing excessive steam from the exhaust.

Also drop by autozone and have them read your computer. Let us know what codes popped up.

the surging and stalling usually only happens when I get to or am coming to a stop.
My "low coolant" light keeps coming on and off ever since I got the tensioner pulley and bypass tubes replaced. I told this to the mechanic and he said the sensor is probably off. I have not noticed any considerable drop in coolant levels in the 2 or 3 weeks after having that service done. I check it every couple days. I haven't notice steam coming out but will keep an eye out.
would there be codes if the check engine light is not on?
I will try to go to an autozone today or tomorrow.

It seems you have not ruled out the MAF. With the engine running, tap on the top of the MAF with the handle of a screwdriver. If it is bad the engine should stall or surge. My 98 LSS had a similar issue and it was the MAF. If you need to replace it, use GM part, they work better.

It seems you have not ruled out the MAF. With the engine running, tap on the top of the MAF with the handle of a screwdriver. If it is bad the engine should stall or surge. My 98 LSS had a similar issue and it was the MAF. If you need to replace it, use GM part, they work better.
OK i will try this. I just drove it to AR from houston. It surged and all that stuff on and off the whole drive. I got back last night. When I started the car this morning a bunch of white smoke came out the exhaust for a minute or two. When I started driving it went away. Any ideas what that is?

If the weather was cool when you started it, it is probably just condensation. The fact it went away suggests that. However, coolant can sometimes seep into the intake, and down into the cylinders. If this is the case you should notice it needing coolant, frequently.

Now, if you tap that MAF, and it seems ok, try unplugging the EGR valve, and drive it to see if it drives better. My EGR valve was bad and didn't throw a code, or turn the engine light on. That also caused a surging, stumble while driving.

I just replaced the upper intake, the lower gasket set,(with the metal frame), belt tensioner, bypass tube, plugs, wires, and EGR valve. I replaced the MAF a year ago.

If the weather was cool when you started it, it is probably just condensation. The fact it went away suggests that. However, coolant can sometimes seep into the intake, and down into the cylinders. If this is the case you should notice it needing coolant, frequently.

Now, if you tap that MAF, and it seems ok, try unplugging the EGR valve, and drive it to see if it drives better. My EGR valve was bad and didn't throw a code, or turn the engine light on. That also caused a surging, stumble while driving.

I just replaced the upper intake, the lower gasket set,(with the metal frame), belt tensioner, bypass tube, plugs, wires, and EGR valve. I replaced the MAF a year ago.
I needed to add a slight bit of coolant after the trip to AR. But have not needed to since (3days) and haven't before.
The dying in the morning and stalling have gotten happened less. I am not nearly driving as much. From observing it for a while it seems to happen more often when I drive at highway speeds for a while and then have to slow down. Does that say anything about it? have not replaced the MAF yet.

The coolant level sounds normal.

If you tap the MAF, and the engine surges or stalls it is bad, otherwise check the EGR valve. Then go from there.

The coolant level sounds normal.

If you tap the MAF, and the engine surges or stalls it is bad, otherwise check the EGR valve. Then go from there.

I tapped on the MAF and no real difference. I unplugged the EGR and no big difference. I just let it idle for a while to see if anything would happen. It doesn't surge all the time.
the problem seems to be getting a bit worse. It seems it is getting kinda jerky. it surged the other day while coasting thru a parking lot and has only starting with the surge coming to a stop prior to that. I am getting a shaking sometimes thru the steering column it seems.

I tapped on the MAF and no real difference. I unplugged the EGR and no big difference. I just let it idle for a while to see if anything would happen. It doesn't surge all the time.
the problem seems to be getting a bit worse. It seems it is getting kinda jerky. it surged the other day while coasting thru a parking lot and has only starting with the surge coming to a stop prior to that. I am getting a shaking sometimes thru the steering column it seems.

Did you drive it with the EGR unplugged or just idle? I would drive it with the EGR unplugged.

Did you drive it with the EGR unplugged or just idle? I would drive it with the EGR unplugged.

No I didn't drive it. I will try that today.

Well I drove it with the EGR unplugged. I went at least about 5 miles. Probably long enough to get a surge from it. But it made no surging and idled pretty smoothly for the most part. Now the check engine light did come on but I am guessing that is just from the EGR being unplugged.
Should I start looking to replace it?

The engine light will come on with the EGR valve unplugged. I would recommend driving it a few days to make sure it makes a difference, then plug it back in and see if it goes back to the surging......

The EGR valves for these are expensive, usually 150-200. That is why I would double check it like I said above.

I drove mine for a few months with it unplugged.....just because I was always on the road.....but as soon as it was plugged back in it would act up.

The engine light will come on with the EGR valve unplugged. I would recommend driving it a few days to make sure it makes a difference, then plug it back in and see if it goes back to the surging......

The EGR valves for these are expensive, usually 150-200. That is why I would double check it like I said above.

I drove mine for a few months with it unplugged.....just because I was always on the road.....but as soon as it was plugged back in it would act up.
I have been driving it around for the past few day with the EGR unplugged. It has only surged a couple times and never more than 500extra RPM's and for just a little bit. It has not died at all. I am thinking this may be the problem. I looked closer at the EGR valve and it looks as if someone put some kind of fabricated metal thin plate in place of where the gasket goes. ??????? I will try to post a pic if I figure out how to do that.

Well today I drove this morning on what was similar to my old morning commute. About 30miles one way in rush hour traffic. the surging came back and it even died one time. I not sure if this is tied in to the prob but the temp gauge started getting high ... like pushing the limit but not quite in the "red zone". I got nervous and put on the heat. that lowered the temp. I am in Houston and it is already starting to get really hot. It was during the time while I was in bumper to bumper traffic. Acted basically the same when I drove it home.
FYI... had the EGR unplugged on the way this morning and plugged back in on the way home this afternoon.
Is this looking more like a MAF sensor? Would that have an effect on the temp?

"FYI... had the EGR unplugged on the way this morning and plugged back in on the way home this afternoon. "

With that info I would say the EGR Valve is not your problem. If you feel like replacing the MAF you could try that, that may or may not fix it....

Well i ordered a MAF but won't be in til monday I think.
today was wierd. After my drive home (apr 30miles) the idling was much worse. Bouncing up and down. Seem to be wanting to die. the traction control switched off a couple times by itself???????
Usually it would just surge and when it came down sometimes it would die. but this time it was bouncing up and down and even making the car shake!!!