Rough idle

[ShelbyDoug]

Before I go and tear everything appart let me ask the forum this. When I start the car cold, usually after it has sat all night, the engine fast idles properly momentarally and then as it tries to idle itself down it will rough idle at 500-600 rpm's, sometimes stalling.
It is as if the computer needs to learn to idle again after the battery is disconnected.
I have learned not to touch the accellerator while it is in this stage. It it doesn't stall from too low an rpm, it will momentarily (20 seconds) bring itself up to fast idle at around 1,600 rpm and then back down to about 1000rpm and run normally.
If anyone else has gone through this themselves I'd appreciate some insight into what is going on.

 

[SHO SPD]

Maybe a bad or dirty IAC valve. And you have correctly set idle?

 

[DigDeez]

And how and what do you clean the IAC with?

My idle is horrible right now also. At startup, it jumps up and down from like 1500rpm to 500rpm, sometimes stalls especially if I don't wait til the rpm stabilizes after like 15 second before shifting out of park.

Can this also be old plugs and wires? Only code is the ACT code.

 

[SHOtimer]

ShelbyDoug,
what year is your SHO and how many miles? The earlier IAB valves are cleanable, but some of the later modles are not as serviceable. They run about $50 for a replacement.

DigDeez,
bad plugs and wires will cause all round poor performance. Do you have oil in your plug well seals?

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=82

Doug

 

[DigDeez]

Hope I didn't hijack this thread; my issues seemed similar. Anyway, checked my plug wells last week, and they were full of oil. I sucked most of the oil out, but little difference in performance. I know I've been needing to do at the least my vcg for a while. Spark plugs have 30,000miles, wires have 86,000miles, fuel filter has 30,000, and o2 sensors have 44,000miles....if this helps.

Thanks for the link. Too bad there isn't a sticky somewhere with all links that have SHO products and info. I sometimes forget about links.

 

[ShelbyDoug]

Mine is a 92, 102k. The intake manifold was just off for BBB and porting.
Everything was cleaned and was reinstalled in good working order.
I will go and specifically look at the IAV though.
This car since new has had a cold stalling problem. I always thought it was the TPS but it has always check ok.
Ford could never find anything wrong with it while it was in warranty.

 

[DigDeez]

You talk about cold start problems. If I understand what you're talking about, I've heard many members here, including myself say that to help with this problem, just turn the ignition key halfway to the on position, wait for like only a few seconds, then start the car up. It helps most of the times with cold starts. Hope that helps!!!!!