Lumina Dies randomly... weird problem

[NeonKnight]

My 91 Lumina Euro 3.1 dies randomly.. its scaring me, i have been driving my 73 Chevy Cheyenne C20 Camper special (with a 454 Big block 4:6:3 gears 12 bolt posi) and the truck is nice and all... but i would like to get more than 7 miles per gallon....

Now the lumina does not have any codes, always checked fluids, refilled when needed, all those kinds of things. timing belt was replaced at 120k miles, car now has 144k, and its not the transmission my car has the TH-125 (3 speed no overdrive) Now for what its doing.

The car randomly dies when warmed up, or at least i think only when warmed up. Once she starts dieing, she will keep doing it if you start her back up. When she dies you can feel a rpm surge sometimes and then she just dies, othertimes i dont notice it like if im in park its a nice and quiet car.

When she dies you can turn the key and start her right back up, and she runs like normal. It died on me a few times, one time i was getting on the freeway on one of those loops that go from an overpass to get to the freeway which is going another direction. she died about halfway through since there was no throttle input.

the other time i was just sitting in the parking lot at 7-11 waiting for my friend to get out of the store, and i went to shift and pressed the gas and she was dead. started right back up though.

the third time i was driving back from a few cities over, i was doing 65 MPH and 3000 RPM all of a sudden i feel a big grab, like something locked up in the tires and i look down at the Tach and wathced the needle bounce fro 3000 right down to about 700 or so and right back up to 3000 and stopped, the car kept driving like normal. so i gave her some more gas sped up to about 80ish since if shes going to be doing this i want to be home or at least closer to it. i felt her give me another one but smaller, so i was about 20 exits from my place, about 5 miles. i let off the gas a little, and the entire way back i can feel these little rpm drops and hear them too, but it was random.

now i went around and checked all the fuses, they are fine. Altenator is new within a year its fine, battery is fine, car could use some new spark plug wires and plugs but that cant cause this, its not ignition related im sure of that.

My grandfather is a GM tech, he was thinking that it could be electrical if it happened that fast. My brother tells me he think its a Vacuum leak, and my neighbor who is a GM tech said it could be a Fuel pump. But if it was a fuel pump could it still make it run fine untill it warmed up?

Im leaning towards a Vacuum line, can anyone give me any insight on this. i really want to get her fixed by this weekend.

Thanks
-Jeff

[tblake]

yes, question for you? 3.1V6? or 3.4 DOHC V6? The 3.1's all come with timing chains I believe, and the 3.4's came with belts. It doesnt matter, but you said euro, so I was kinda wondering if that 3.1 was a typo. Ok, next, Dont rule out the spark plugs and wires. Actually, as I was reading your problem, I immediatly thought the plug wires may be arching over to something when they get warm. Do yourself a favor and if the plugs and wires look bad, chances are they are, and spend a little time and money and replace them. It may solve your problem. If nothing else, give you better gas milage and rule out plugs and wires as the problem. AS for a fuel pump. They are usually either completly good and working, or completly bad, not many cases of in between. You can hook it up to a fuel pressure guage and see if there is enogh pressure there. I think around 40psi is the spec. Not sure. Could also be a sticky injector, have you tried fuel injector cleaner lately? Get some that wont harm an o2 sensor, I was using some one time, and my o2 sensor took a crap. Good luck.

[starla3366]

I can't see this gripe ending up to be just a vaccum leak. As a vaccum leak would be the most likely cause of a high idle, and not a engine stall. I just did a search for "fuel pressure" ( http://www.automotiveforums.com/vbulletin/search.php?searchid=1182853 ) and found some usefull information. Check it out

[maxwedge]

How old is the fuel filter, test the fuel pressure to get a general idea if the pump is getting weak.

[NeonKnight]

Yea Tblake, its the 3.1 The Euro edition just had the same Suspension package as the Z34, but with 15 in rimcs instead of the 16. they look exactly the same though.

One thing also, thre old owner of the car was my neighbor and at 120k miles it had a major tuneup done, she said shes not sure if the PCV ever got replaced. and im wondering if that can do it also? maybe cause some kind of weird thing. i know that it can cause high idle if clogged. but i will check into getting wires, and maybe even some new plugs. I just hate doing the rear plugs and wires... just gotta rock that engine forward for an extra 4 inches hahaha.

the Fuel pressure is fine, it was like 40 psi i think my brother said. im not sure

[skyehi]

me too, same problem, will apreiciate any imput!
dies randomly

[jeffcoslacker]

A vacuum leak is overcome as soon as the throttle plate is open, so if it dies under any throttle, it's most likely not a vacuum leak.

Why do you say it's not ignition? That sounds most likely, like an intermittant loss of crank sensor signal or module control.

Usually (but not always) an iffy fuel pump will lay down on acceleration, then refuse to start for a while till it cools a little. Might be worse the lower the tank is on gas.

I'd start by putting a fuel filter on, regardless of how old or new the current one is. Then I'd check the battery terminals and any other primary power junctions I could get to easy. Then have a look at the CPS and module connections/wiring.

See if that turns up anything.

[NeonKnight]

Even if the sensor is losing signal. wouldnt that throw out a code? hmm well im going to replace the PCV since its $2.99 at autozone lol. then im going to look at the prices on a CPS, and i have been wondering if the ECM could be going bad, or have a bug in the PCM. i mean she high idles but only by a couple hundred RPM, doesnt always start up right, wont go up to 2k RPM and drop down like she used to, she might go to 1500 and just sit there for a sec and drop to 1200 - 1300 and just start trying to idle there. after about 10 mins or so she goes a little more down. i dunno im tired of driving the truck and i miss my lumina... im attached to my baby

[NeonKnight]

thats the other thing Jeffco, if im sitting there waiting for her to die, and i see the RPM flux and gas it she wont die. she has never died on me with throttle input. the freeway thing was the only time she did anything with throttle input

[jeffcoslacker]

Originally Posted by NeonKnight

thats the other thing Jeffco, if im sitting there waiting for her to die, and i see the RPM flux and gas it she wont die. she has never died on me with throttle input. the freeway thing was the only time she did anything with throttle input

Oh, OK. That makes more sense. It could be a vacuum leak then. EGR and IAC would be likely suspects.

If it died when you lifted off the throttle that time on the freeway, that would put that episode in the same area of suspicion.

The PCV is a good idea. I've never bought one for my own car, I always just flush them with carb cleaner and put it back in.

[NeonKnight]

is it possible that maybe the EGR or IAC is going bad and at some point allowing an electrical current through the engine. or shutting down the current? i know Vacuum leaks can do odd things. but my grandfather who was a GM tech for 30+ years says it sounds electrical. im not sure but a lot of things make sense lol

[richtazz]

your ECM is under the hood on your car, and since it's 15 model years old, I'd check the wiring harness to the ECM. IT is located under the radiator overflow bottle on the passenger side. While your in there, check the bottom side of the underhood relay center for possible corrosion. This of course is assuming that you have had the ignition module checked and you've replaced the crank sensor. The crank sensor comes out with one bolt and costs about $15. Change it, that eliminates it from the equation.

[NeonKnight]

Picked up a $20 CPS and a $2.99 PCV total was 24.99 exact after tax lol. so im going to throw those in, and i checked the relay center no sign of corrosion same with ECM the wiring looks fine.

im going to talk with my grandpa about checking the Ignition module checked

[NeonKnight]

Earlier i had my car in park after taking her for a drive, and she died when i tried to shift her in reverse because i wanted to go to the gas station.

She only dies and acts up if she is warmed up, otherwise she is fine. so im going to keep driving her for short trips and nothing more. and my first Gear if i throw it down into 1st on the Steering Colum makes a loud high pitched whine.. is that bad? in drive its fine but yea lol any ideas on that one?

[NeonKnight]

okay took the ECM to autozone to figure out that they dont test them... well w/e they can go screw themselves for now i slapped it back into my car, relearned idle and the car seemed to run fine. so i took her for a longer ride where she could get warmed up nicely. on the way back home i felt a grab 2 times 1 a few seconds after the other, but didnt see the RPMs jump. im wondering, could this be the TCC? i know i can just disconnect that jumper and see if she still does it. and if not then im good. My only concern is that i dont have any SES codes comming up at all. and im hoping that if i dont drive her and it is the TCC that i can repair it myself without having to worry about much.