Originally Posted by Bob Dillon
Sorry to sound like a broken record in this forum, but check all around for vacuum leaks.
What'* the best way to do that checking, Bob? I ended up hooking up an old vacuum/compression tester in the line where it goes...I don't know, to some kind of transmission switch? There was a badly degraded piece of hose there connecting two ends of hard line, so I replaced it and tee'd in the vac tester. The car was cold, but before I started it I removed the MAF and used CRC MAF cleaner and sprayed it down pjretty good and replaced it. I didn't let it die when I first started it; and it finally leveled out around 1000 rpm and pretty steady, though the engine speed would kind of float, its response lagging my input at the gas pedal. The vac tester read just in the grean, about 18-19 Hg/mm (I think those were the units). As the engine warmed up a little I could see the vac drop to about 16. I'm checking stuff all over the place and noticing how the whole "missing" business doesn't seem as bad since I cleaned the MAF, but still noticeable. The engine'* getting warmer and I look at the vac and it'* oscillating very rapidly from about 10 to 16 contantly, not rhythmically. What is that?
I pulled the connector to the IAC and there was no effect. So I shut down, removed the IAC. It was very hard to move the plunger, so I sprayed it down with TB cleaner and worked the plunger in and out a little. But I ended up pulling it out so I sprayed it some more and put it back together. It was a lot easier to move in and out but still pretty stiff. Is it supposed to be that way? I reinstalled it in the TB and started the engine. Idle was steadier and smoother than before; but the most remarkable thing was that engine speed followed my foot on the gas pedal much more closely, even normally, I'd say.
One thing I wanted to say to BillBoost'* question was that the two vac connections to the TB are not in great shape, but I'm having a real hard time finding replacements. A Pontiac dealership nearby had the same difficulty locating the part in their system as I did trying to find it in my FSM--except they finally found something. But it doesn't look like my setup at the TB. When you say "U bend" what do you mean? Both of my TB connections are "L" shaped boots. They seem to fit faily snuggly, but I will order the part, or assembly that they found, to see if it can fit.
There'* a new wrinkle I've noticed: I've had the engine heated up real good three times now since finishing the UIM/LIM job and only the second time did the larger, driver side, radator fan come on. The other two times neither fan came on, and both those times I could see a light vapor rising from the area of the top of the radiator. It kind of looks like coolant vapor, but smells like hot plastic. And I can not identify any leaking whatsoever.
I've noticed improvements related to both the MAF and the IAC. I'm wondering about the O2 now. I think I'll have to try to find a scanner.