1990 Lumina Acceleration Problems, help!

[a_duncan]

I have a 1990 Lumina (Euro, 3.1) that's very recently had the ignition module, crankshaft position sensor and air intake hose replaced. Now, I'm having problems accelerating, it's very sluggish and doesn't seem to shift gears very easily, the engine is revving when stopped at a light, it's jerked a couple of times while accelerating (usually fixed by accelerating very, very slowly) and has "jumped" RPM's a few times. The car was not like this two weeks (that's how long it's been out of use) ago! It used to be very smooth to drive, no problem.

The transmission fluid is fine, the spark plugs are also fairly new (though the wires have never been changed) and I'm about ready to set it on fire and try and collect insurance on it. Please, if you have ANY ideas, help me out, I really don't want to go to the mechanics for the third time in two weeks (and neither does my bank account!)

Thanks,
Ashley

[lanerd]

Well just shooting some ideas here, this includes tricks done on multiple GM vehicles, I do have a lumina but the ICM fixed everything....
Jerking- Sounds strange but tighten the battery terminals. Had a chevy express that liked to buck and tightening the terminals down fixed that.
Jumping at idle-On my lumina, it was running which, therfore the computer was looping to compensate. Replace o2 sensor.
You may also try changing those wires, if they're original they may have just given up the ghost over the passt 2 weeks. Hope any of that was a help!

P.S Insurance adjusters can tell when you set the fire, have a friend do it... cough cough

[richtazz]

Check to see if you accidentally caracked/disconnected a vacuum line while working on the air intake hose. There is a vacuum junction at the throttle body that spilts and goes to the transmission shift modulator, HVAC system, and emissions canister. These lines are made of hard plasitc, and crack easily with age. The resulting vacuum leak will cause everything you describe.

[d12x12d]

Originally Posted by richtazz

Check to see if you accidentally caracked/disconnected a vacuum line while working on the air intake hose. There is a vacuum junction at the throttle body that spilts and goes to the transmission shift modulator, HVAC system, and emissions canister. These lines are made of hard plasitc, and crack easily with age. The resulting vacuum leak will cause everything you describe.

this is very true, i had the same exact problems with my 92 lumina euro before its transmission went, i ended up replacing the vacuum lines while i was doing some other smaller repairs, it ran alot better after that, but then my trans died, so i did an engine swap and all with my 93 lumina base model

[morjackson]

Good point on the vacuum hose.
I had a fuel injector replaced last week and it started running rough yesterday and got worse today. Not bad enough to stall unless at idle but does fine when driving.
Smooth at fast idle amd very rough at slow RPM, drops from 1100 RPM to 500 and shakes like crazy.
I looked under the hood and found a broken vacuum hose. Not good but does explain a lot. Now to find the other end of the hose and things will be fine. The end is broken unevenly and about 9" long. It'll hang under the air filter box but I can't figure out where the other end of the line goes. Frustrating as I can't find it in the manual either.

[morjackson]

I forgot to mention above when I jumped the computer, I have codes 33 (MAP Sensor), 35 (Idle Speed Control Circuit), & 44 (Oxygen Sensor - lean exhaust indicated) showing up. I think those can be tracked back to that broken vacuum line.

[morjackson]

I think I fixed it. The hose goes to the transaxle. Easy fix. Just had to think like a broken hose. LOL