On today's episode of WTF is wrong with my car....

[joemomma]

So, this morning leaving for work, fire the car up and it's idling what I would call "rough", almost like it has way too big of a cam. No miss, just running rough like an old carb setup that isn't warmed up yet. Give it a light rev and it clears up some, so I proceed to back out of the driveway. Still running rough, I stop at the upstairs garage and pop the hood, thinking maybe #4 plug wire is off again causing it to miss. Nope, everything is good and tight. Close the hood and drive on in. It is running fine, by the way. No loss of power or anything of that sort. The only issue I notice is the idle is hanging and it's idling higher than normal. Normal on this car is 900 or so, and it's hanging around 1200-1300 RPM when at a stop light. Hop in at lunch, and it's idling rough again with the continued high idle and hanging revs. After lunch the rough idle is gone, but the revs are still hanging. I have a suspicion that when I leave after work it's going to idle rough, and still have high idle/hanging revs.

Am I looking at a vacuum leak here? Car seems to run fine otherwise.

 

[PinkieT]

Vacuum leak sounds likely to me.

 

[joemomma]

A few of the guys over on S197 forum mentioned a dirty IAC, so I'll clean that while I'm at it. I had cleaned it last year when I was chasing idle issues, maybe it's dirty again. If cleaning it doesn't help and no vacuum leak, I'll throw a new one on it. They aren't terribly expensive, and it is likely due.

 

[joemomma]

Cleaned the IAC with no change - it appeared to be the OE unit, so I'll just replace it. I didn't have a chance to put the smoke machine together over the weekend.

 

[lwarrior1016]

Cleaned the IAC with no change - it appeared to be the OE unit, so I'll just replace it. I didn't have a chance to put the smoke machine together over the weekend.

The aftermarket idle valves are hit and miss as to when they work. Motorcraft would be your best bet.

 

[joemomma]

Ordered a Motorcraft one this morning along with a new Motorcraft TFI module. I figure I'll go ahead and replace it while I've got the air filter and stuff out of the way. It looked to be original too.

 

[ttocs]

Cleaned the IAC with no change - it appeared to be the OE unit, so I'll just replace it. I didn't have a chance to put the smoke machine together over the weekend.

just get a cigar, or invite your friend over that still smokes.

 

[Rod]

Try cleaning your MAF sensor wires. I have had idle issues over the years that a good, gentle, cleaning cured.

 

[ttocs]

lol I wonder why he has not tried that yet?

 

[Rod]

IDK. There is a lot of things on the interwebs that say never clean just replace if testing is out of range....BS. Just don't be stupid about it.

 

[joemomma]

Cleaned the MAF wires last year while chasing idle issues, but I can clean it again for grins.

Replaced the IAC valve and did a base idle reset, still rough idle. I didn't go for a drive but I'm assuming the revs are still hanging. I'll get the smoke machine assembled this week hopefully and chase down vacuum leaks.

 

[Daryl]

Nah… car’s dead. Get anew GT500 instead!! ROFLMFAO!

 

[bybyz06]

Sounds like a TFI. You can do a visual check by popping the cover off the front and look at the film. You’re looking for what looks like exploded cities in the film; if present the TFI needs to be replaced.

 

[Rod]

Oh man! The mention of the TFI made me think...is the timing spout in it's socket? If the initial timing is set really low the engine would be really lopey, it sets the idle higher for setting the timing, and the over all power would be down because the timing wouldn't advance.

 

[joemomma]

It is present, looks to be original. I have a Motorcraft replacement waiting to be installed.

I built my smoke machine but didn't really get a chance to test it, it was leaking lol. I need to seal it up better then I can do vacuum leak tests.