poor idle at startup
 

Stang in sig has poor idle at startup. Idle bounces between 500-700 rpm's. Sounds like car might die but it doesnt. Once car is warmer (2 min) it will idle perfect @ 750rpm and will be fine from then on. It's basically ONLY during startup for a min or two. Plugs, wires, dist cap, fuel filter all pretty new. Could the MAF be tainted due to K&N filter oil? Any thoughts?

won't hurt to clean the maf meter/use an air intake cleaner spray/not carb cleaner,and don't touch the wire,clean the throttle body too.may take a bit of time to learn new idle after cleaning.

Might wanna try to clean the IAC module.. My truck was doing the same thing.. Cleaned it with brake cleaner and pipe cleaners.. Just like new.

Bradley

I have GUMOUT throttle body cleaner already, can I use that on the MAF? And how do you clean it, just spray while car is running or off? or do i just remove it from the car and clean it on a bench?

Also with the IAC, anything cleaning tips or tricks? Remove from vehicle and clean with brake cleaner or can I clean it on the vehicle?

Any info or maybe a link to a write-up or posts would be great. thanks in advance.

IAC need to be taken off to clean throughly. It's simple, just take off the 2 8mm bolts and unplug it and it will come off. Just be sure to check the gasket when you remove it. I would just get a new gasket from the parts store when doing it. Especially if that is the original gasket...

thanks coolbreeze, I'm gonna give that a try this weekend. So should i use brake cleaner on the IAC or will throttle body cleaner be fine?

When cleaning the TB in the past, I followed the directions on the can of TB cleaner. it said run engine, spray for 10 sec while working TB, wait 10 sec w/ engine still running not to overheat cats, and repeat till entire TB cleaner aersol can is empty. That seemed like a lot of cleaner to use so I only use like 1/5 of a can. but I do notice that the TB will get a little gummed up after about 6 to 7k miles. Will I get better results if I remove the TB and clean it in a different manner? For the record, all parts are original w/ 118k+ on them. Almost positive IAC and MAF have never been cleaned or removed!

I never cleaned the Tb like that. I just put some TB cleaner on a rag and open the butterfly & clean it manually. Just soak the rag real good and use a dry clean one to wipe it out, repeat until clean. But that is just me and the way I do it....

On the IAC you can clean it with what ever, but I always use TB cleaner. When you get it off there will be 2 holes, just spray into them until clean.Also move the plunger up & down while doing it to throughly clean it. When I clean mine I always take it apart, by the 2 little screws, you will see what I am talking about when you get it off.

I had that problem once and did all the usual things.... it turned out it was a vacuum leak for me... well the hose had rotten apart... right below and behind... or in front:confused: the distributor... hooked it back up and didn't miss a beat after that

-Mike5p0

well i'm going to remove the Tb and EGR plate and clean them well with TB cleaner. i'm also gonna test the egr valve with a vac gauge if i can find one around. might as well clean up the MAF with some alcohol and a q-tip (gently) and throw on new gaskets all around. they all are original and except the TB have NEVER been serviced. how does that all sound?

Not sure on the FOX bodies, but on my '95 I remove the MAF sensor from the housing by removing two T-20 torx screws and disconnecting the electrical connection then use electrical cleaner or heavy duty brake cleaner on the sensor to remove the crude. Just don't damage the little wires on the sensor.

I had a VERY similar problem with my 92 GT and like mike5p01, mine was a vacuum leak as well. I like to start off with easy stuff first, then move to all the sensors and module crap. CHeck the hoses (the rubber hose that had rotted on mine was the one coming from the intake and going to the emissions box). It started off like what you are talking about but then just got worse and worse where my car at a stoplight would surge and idle high then low then high. By that time, though it was obvious that it was a vacuum leak. IF you haven't already, check your rubber vacuum hoses first.

well, for starters i reset the computer by disconnecting the neg battery terminal and leaving the lights on for bout 30 min to drain the capaciters. this was never done when i changed my o2 sensors a few thousand miles back. now the car runs worse, it usually dies at first startup unless you give it gas and will idle poorly at around 500 rpm's when warm. i only put about 70 miles on it since disconnecting. how long does the computer take to learn everything over again and run correctly?

well, for starters i reset the computer by disconnecting the neg battery terminal and leaving the lights on for bout 30 min to drain the capaciters. this was never done when i changed my o2 sensors a few thousand miles back. now the car runs worse, it usually dies at first startup unless you give it gas and will idle poorly at around 500 rpm's when warm. i only put about 70 miles on it since disconnecting. how long does the computer take to learn everything over again and run correctly?

Check the Corral,, they have a good idle reset tech article....

well I picked up all the necessary gaskets and this weekend i'm gonna take off the MAF, TB, IAC, EGR spacer, EGR valve, and upper intake and give them a cleaning.
1) how do you test and/or clean the EGR valve? should i clean the EGR spacer and upper with some TB cleaner as well?

2)also, i wanted to replace everything i can while the upper intake is off, anything i should change or look for?

3)and finally, how many vaccuum lines are there and can someone be a little discriptive with the locations? i figure i will replace all of those orig. rubber pieces. thanks.

iac??
 

what should u use to clean the IAC ? brake clean ok ?
i think i missed what u cleaned it with in the threads above

well, took the IAC off and cleaned it with TB cleaner. it was pretty dirty, but i think i could have gotten it cleaner, i just took the 2 screws off, broke it in half by removing 2 more screws, and sprayed the piss out of it, cleaner but still gummed up i think, anyway to clean it better?

i also cleaned the TB while on the car with TB cleaner and the MAF with elec contact spray. i didnt have anymore time so i connected the batt and problem solved! idles around 800 rpms which is good cuz when I put heat on MIX or DEFROSTER, the car will drop about 200 rpm, like its being drained. only on MIX and DEFROSTER, not floor, vent, etc. RPMs dont even drop that much with the a/c on! any suggestions?

I had the same problem and tried all the above and nothing worked and I found out it was a vacum line that was attached to the upper intake running from the smog box installed under the smog pump, after removing that and pluggin it off my car idles perfect no matter how long since the last time its been started