Occasional rough idle after warm restart - any ideas?

[arussell]

I can go out and cold start my 94 w/ 84K mile in 10 degrees or 70 degrees and it runs fine. Occasionally after the truck warms up, is shut down and then restarted, it runs like crap: low idle speed, serious shake. Getting on the road and getting up to speed gets rid of the problem, but it can't be good.

The problem is, it only happens occasionally. One day I take it out and it's fine, the next it happens, then I won't see it for a few days again. I can't seem to put any logical cause or situation to it. I was thinking it might be some of the s*@# gas they sell out here in Colorado, but I've put in low octane and high octane & still get the same problem. I keep reading about some of these sensors getting dirty or going bad (O2, MAS, IAC). Could it be one of these? I just got the truck through family and know it has been maintenanced (at least the routine stuff) and I just had a tune-up on it. I'm sick of paying the dealer money to not fix things & want to do it myself.

Thanks for any suggestions.

-Adam

 

[drwambo]

I'd love to know the answer to this as well. My 96 EB does exactly the same thing. I'm off today to have the injectors cleaned and clean the MAF and throttle body. Any other thoughts out there??

 

[Kontrol-Trak]

I had the same problem...cleaning the IAC valve solved it

 

[Fordman6996]

:exp:
I have the same prob on my 94 limited I can start it cold and it runs fine, then after its warm and I shut it off wait for about 5 to 10 mins then go to restart it runs like crap rough idle the rpm gauge reads under 1,000 also some times my voltage gauge goes down to 8 does yours? its pissing me off as well also I get a rattling sound when I drive sounds like the bearings are going to lock up, you can really hear the sound from the passenger side wheel well but for the rough idle I have a idea it might be the o2 sensors or the egr, I just put in a new mass air flow sensor and it still did it I'm to the point where I'm just going to overhaul it my X has 116k.

 

[drwambo]

Guess what - I cleaned out my IAC, and so far so good. hasn't done it since.

 

[Fordman6996]

:exp:
does the 94 V6 have a IAC? and if they do where is located

 

[drwambo]

haven't a clue, but I would assume so since it's the same motor as mine. It's located on the driver's side of the throttle body. attached with 2 bolts and an electrical connector.

 

[checkedout]

Had the same thing on my 96 XLT. I tried everything and it wouldn't go away until one day while it was doing it I took a wrench and tapped on the IAC and the idle jumped right up! A few days later I stopped by the dealer to pick up a new one but it cost 130 bucks! The parts guy said that the mechanics just blow them out and put them back on. It's been about a month and it hasn't fail again yet. If it does I'll just clean it. On my 96 it's located right on top of the engine. It's a little silver cylinder with a black knob on the side.

 

[drwambo]

Anybody know what the little black knob is for???? Always wondered about that.

 

[arussell]

Fordman-

I don't have the voltage drop you are experiencing, but I'm going to take some time to put on some new shocks and clean the IAC tomorrow, so I'll let you know in a few days if it solves the problem. From what I've heard in this thread and the research I've done, it sure seems like the IAC may be the problem. I'm hoping cleaning it will take care of it, as I don't want to spend $130 on a new one.'

-Adam

 

[rjc]

Looks like this is probably going to be my problem too. Must be a common problem. I'll go see if I can clean. rc

 

[rjc]

OK, looked at the air intake and could not remove the mass air flow censor due to the use of those damn center post torque screws. Now what. I also am not sure what I cleaned but I removed something called the CTS but really wasn't sure how to clean it. Is this the same as a TPS? Does that stand for throttle position sensor? Thanks, rc

 

[Fordman6996]

:exp:
hey everybody, well I've been researching and I'm guessing it going to be the IAC valve there also right behind the IAC valve theres a ICV valve it threads right into the air intake that might be bad to I took off my IAC valve and cleaned it with some air intake cleaner went and drove it then came home let it set for a while came back restarted it, it did it again but it wasn't so bad I'm guessing I need a new one of those also I came into another prob I have a rattling noise when I drive you can really hear it when I'm driving around 65 75 you can really hear it good when I step the pedal to increase speed but not to make the rpms jump to 3,000 my dad is a old school ford mechanic and he thinks its the EGR making the noise but it sounds like it from under the car, so if you guys have a clue what it is please let me know its not the shields on the converters cuase I cut them dam things off along time ago. but this weekend I did buy a chilton manual for my X and man you guys should get one as well it tells you how to test the IAC sensor and egr also how to rebuild the motor and tranny doing brake jobs wiring diagrams and vaccum diagrams I think its a good investment soon as I get some time I'll be doing some testing on those sensors. I just might pull the air intake get it cleaned. let me know on your guys progress k.. cyas