So my 94z has decided to go flaky on me, with a crummy bumpy idle when in drive (not park for some reason) and an intermittant bumpy missfire in low/mid rpm ranges. The car also seems to struggle to get up into the high rpms recently it seems almost like a breathing problem or something. I've done e3 plugs, wires, msd cap/rotor just the other day, and the coil. I'm stumped! Ideas?

 

It still might be the optical spart... atleast the non mechanical portion of it. When mine was acting up it was hell getting it to go to higher RPMs... but if you have a missfire for sure try dropping the car in 6th gear at about 50... and see if the car shakes at all. The only other thing to do is recheck everything... make sure no plugs are cracked., or melted wires. best thing to do is to pop your hood at night and look for the fire works.

 

How's your fuel pressure?

 

What about if you go to WOT? Does it go away?

If it does, Id be looking at O2 sensors.

Sure there is no vacuum leak? Check the intake, everything from the MAF up. If there is something questionable, spray brake clean on that spot, the idle will shudder/sputter if there is a leak.

How often do you run injector cleaner through it?

Check the fuel pressure with a gauge. At WOT it should be like 30 something. Key on, engine not runnin it should be around 42-45ish

Is the fuel filter clean?

Make sure all connectors are on tight. My truck did this once and it was because one of the wires popped out of the connecter for the MAF.

 

That would cause a SES light. He didn't say anything about a light but hey, we are working with pretty little info.

 

thanks for the suggestions, there is no ses light, or codes hidden i recently put it up a a scope to see what the problem was. I was told the coil, replaced it and still the same issues. The problem sometimes goes away with wot sometimes...

 

I'll check the pressure and see if i can find any vacume leaks

 

Clogged cat.

 

I woulda thought that as well but i just got a high flow one installed recently to pass aircare:blah:

 

I'm not familiar with the e3 plugs. Years ago when my engine was near stock I installed a set of Bosch platinum plugs...car ran like sh*t. Replaced the plugs the next day with AC Delcos and the car ran great; didn't find a single loose wire connection while removing the Bosch plugs either.

 

I've heard that too from my mechanic. My smyptoms seem to be getting better after i took off the battery and the computer is now learning things again i guess. Seems still kinda slowish though, when i was having the missfires the car would be amazingly quick when it diddn't have any issues, now its better, but it seems like theres less power?

 

I had this same problem, sometimes it would just vanish if I floored it, sometimes the motor would stall. I ripped the opti apart and cleaned it all up, put it back in, and the problem was gone.

 

hummm, yah i installed a vented kit from msd when i did the cap and rotor, it seems the more i drive it the better it gets. Fingers crossed

 

Good luck. With the Opti's track record, you're gonna need it.

 

One thing i find that is werid is the fact that I never have any problems when the car is in park or neutral, i can rev the engine easily and quickly, not so in drive.