Hey all -

I've been having a random stall issue when the car gets warm - 5.7 TPI - I took my MAF out, cleaned it up, got a bunch of dark junk out of it. Drove it around and the car was behaving much better.

Figured while I was in there, I would look at the IAC. It was really nasty and beyond cleaning, so I bought a Standard Motor Products IAC replacement.. replaced it, did the factory idle procedure. Got IAC to open, unplugged, idled the car down to 450 and turned it off. Reconnected IAC and the car stumbled a bit the first couple of starts but ran really well after.

Took it on about a 40-50 mile round trip drive. A few times at a stop, the car would stumble and kind of lunge forward.

So I'm sitting here thinking what it could be.. TPS? Maybe I didn't get the car as warm as it needed to be when I set the min idle?

It's running better than it was before, by far, it's just lunging at stops.

 

Did you adjust the TPS?

 

I didn't, does it need to be re-adjusted when the IAC is replaced?

 

The replacement of the IAC should not affect the TPS. However, if would be prudent to check the signal voltage there to verify it is in the correct range.

Since the MAF was apparently dirty enough to affect its operation, and the IAC was so dirty that it wasn't worth cleaning (never saw one of those), it would stand to reason that the throttle body itself would benefit from a thorough cleaning and inspection. The air passages, blades and shaft, and bores should be cleaned and checked to insure they are unobstructed and moving freely.

What kind of air filter is installed? That might be worth checking as well.

 

I'll check the TPS, worth checking for sure.

The MAF had actual chunks coming out.. which I thought was interesting, it didn't appear that dirty to the naked eye, but the car seemed a little happier after the fact.

I did clean the throttle body, on the intake, so not as good as it could be, but it is significantly cleaner now, the air passages and blades were a little dirty.

As for the IAT.. too dirty to clean? Maybe not.. but I found a new Standard IAC for $30, it wasn't worth the hour that I would have spent trying to get it perfect.



I have a K&N drop in filter. I have no doubts that the oil probably contributed to at least a little of this, specifically the MAF. But the filter is clean and in good shape.

I think I'll take a look at the TPS next, cheap enough to replace if needed.

 

If you adjusted the idle and played with the adjusting screw, that will affect the tps reading.

you'll also need to check timing too i believe

 

Save the old IAC if you haven't already tossed it. Current replacement parts sometimes don't perform quite the same as the originals, and that one could be cleaned, spring adjusted, re-lubed, and put back into service.

I had a K&N in my '86 for a while, but went back to a paper element after a MAF failure. I'm not saying the oil on the filter did it, but it was suspiciously coincidental. I did open the filter housing base for a little better flow, however.

I just noticed that you're in Janesburg, just across my Ill-Noise border. You might see another red TA up and down road before summer is over, as it'll probably get a couple short trips that way soon, but not until the EAA madness clears out of my old hometown.