Sorry about length.

Symptom
I have an 88 Iroc with the 5.0 TPI (please note that the muffler is off and someone gutted the cat) I think the car is missing. It has lost power, Mpg, and shakes. At the same time it's running really rich. You can hear the car running poorly (i'll post sound files tomarrow) I get this in eather hot or cold, idling in and out of gear and while accelerating. Also when i'm driving and i'm low in what ever gear it starts to shake and stumble. I can feel slight surging when drving at any speed and when accelerating. Also a ticking or knocking sound can be heard.

When It Started
This all started after I removed the intake manifold so a shop could fix some aluminum around the thermostat. When i was dissasembling the engine to remove the manifold i noticed the distribiter has some rust on the pickup coil but not on the ignition modual.

What I've replaced
I have checked the timing, and firing order many times now. I have also replaced the cap, rotor, wires, and spark plugs, and PCV. They have had no effect. The O2 sensor looks new but i don't know how new (bought the car last april)

What I've tried
I've heard some people say that the egr can do this and to pull the vacume hose going to it. I did it and they have had no effect. I felt the fuel injectors for ticking and i could feel it on the drivers side and could not feel the ticking on the passenger side. Also two hoses that go from (one from egr vac lines and the other from throttlebody) are they both supposed to have some kind of vacume? The one from the throttle body does and the one from egr vac lines doesn't. And my car does not have the sticker that shows vacume hose routes so if anyone has a pic of that. it would be helpfull.

Basicly HELP ME. I need an expert :hail:

P.S. I tried to adjust my minimum air and when i started the car after unplugging the IAC the car dies. I have to manualy idle the car at 1100 rpms or so.

 

Well worst case it could be part of the rotating assembly going, however I don't think it's that bad. The 02 sensor most likely isn't causing the problem. I'm not an expert on TPI, but I would first suspect the MAF, IAC, or TPS (not quite sure if the TPS would have anything to do with it). It could also be the pickup coil or the coil itself. I would check those first though since they're fairly cheap to replace.

 

do you know you have a dead hole or are you just guessing? since you said it has a dead hole and you should know which one it is swap a plug and wire and see if it helps. if not try a compression test on the dead hole. actually all of them but i'd start with the dead one.

 

i'm not sure which one is dead (due to the fact that after 2 shocks with the old plug wires i stopped) but i do know that when i got the car in april i had my mechanic do a compression check and it read 165 on 6 and 170 on 2 cylinders.

 

Compression should be within 10% IIRC on all cylinders, so it sounds like that's not the problem. Most likely it's ignition related.

 

can the coil or modual cause a constant miss?

 

we had somewhat the same problem after my dad installed his module on his 91 suburban 350tbi sounds like the same symptoms the truck had and the new accel module was teh fault. I also had problems on the firebird. I've already done a msd blaster coil on the rs and am going to do a module soon. See if theres any of that white dielectic?? grease on the ignition module without it the module can over heat. I'd say replace the coil and module or atleast have them tested first that doesnt cost as much as other things!

 

i found the problem, it was a loose injector wire. Thanks anyway for the help