I had a high idle since I got the car, and it stuck. So I replaced the Throttle Body. Since then it no longer stuck, but the idle was still high. I replaced the TPS and that seemed to do nothing. I also replaced the IAC. The problem is when I start the car and go for a drive, about 5 minutes into it, the car will bog extremely bad. If I clutch it, the rpms go way down and it will fluctuate up and down a small amount. But attempting to move only causes the car to jerk back and forth in a very unpleasing way. Also, I can keep the rpms up and go WOT with no bogging problems, but anything less than WOT and it has trouble. It sounds as if its misfiring or something of the sort and a buddy behind me said he noticed an abnormally large amount of black smoke from my exhaust. The car had never smoked before. I'm stumped. Don't know what to do. I've read some things about adjusting idle but I'm not really clear about it. Also, I've heard of a difference in the cold start idle and running temp idle? I don't know. I'm asking for help and opinions. Thanks ahead of time guys.

 

Does anyone have any ideas at all?

 

Maybe check the collant temp. sensor. This would make the car run rich once it heats up. Not sure if it would run that rich though.. If it was ignition, I'm pretty sure you'd have probs with full throttle as well. Or it could be the fuel pressure regulator. I had the same prob. with my 81 280Z it would idle really low, and up and down a bit. HTH.

 

When is the bogging happening? Off the line? Mid RPM? High End?

You may have a timing problem if it is rpm happy. You may want to advance your timing a few degrees and see what happens. After you do that, readjust your TPS and IAC.

 

The bogging happens low to mid RPMs. But like I've stated, it only happens after a few minutes of driving. Ittle be fine through the entire rpm range until then. If I turn the car off (or it stalls on me....) I can turn it back on and I'll have another five minutes or so.

EDIT: I didn't mention before, but I replaced the TB with a BBK 52mm.

 

No codes at all?

 

black smoke is running to rich,whites oil. so if your running that rich maybe its the o2 or collant sensor like someone else said. timing also.