ive searched this and cant find a clear solution. I purchased my car with some mods on it including the MP 60 mm throttle body. therefore i havent much of an idea of what customization was needed for it to be put on. im trying to replace it now with a stocker. I got it all bolted up, but car wont keep a steady idle without the gas being pushed in some. when let off gas, car dies. now i notice theres some slack in the cable, not much but its there. any ideas?

thanks.

IAC isn't working properly.

Yea, its either the IAC not working properly or the throttle plate is not adjusted correctly and is fully closed at idle.

First thing I would do is tighten the idle set screw a bit to see if that helps. Also, while you are at it, you might as well adjust the throttle cable so that there is no slack.

If you still have troubles after this, check the IAC to make sure it is working. If it OHM's out, then clean it with brake cleaner and reinstall with a new O ring.

Also, just out of curiosity, why are you going from the MP 60mm back to the stocker?

Its the IAC! Try screwing the tip in just a tad.

Send me your MP 60mm and I'll tell you what the problem is :evilgrin

did you clean out the throttle body and iac out real good when you put it in. Like the people above posted it is either one of those. Why did you want to downgrade to begin with? i would just slap the mpx one back on.

Could be the IAC, But I doubt it. If there is slack in the throttle cable, then the cable probably is not pulling the throttle plate open a little bit at idle to keep air flow coming in. Loosen the two bolts that hold the throttle cable down to the intake manifold, and move the cable until it seems like it is straight or stiff. Then try retarting the car and see what happens. If that is not the issue, then yes, it could be an IAC issue, or a cracked gasked, and causing a big vaccum leak.

I agree with Mike. Definitely loosen those two bolts and tighten up the throttle cable. But, like I said above, also make sure the idle set screw is adjusted properly. You may just need to tighten it a little bit so that the throttle plate is slightly more open at idle or when off the gas.

I dont think it is a vacuum leak because if it was, it wouldnt be an issue of not being able to idle, it would just idle too high.

i wanted to pull it because i may be selling the car to start a new 420a project and wanted to just pull it for it rather than buy another. idle is set fine now. now the problem is car doesnt wanna climb past 3900 rpms. in every gear it climbs to 3900 and once there it stutters and jitters until i shift.

Check map sensor

Also have a friend tell you if the throttle plate is fully opening when you floor the gas pedal.

Did you ever adjust the throttle cable?

Factory Throttlebody should have the throttle plates fully closed at idle. Apparently we have a lot of people on the site that have never looked at their throttlebody before they screwed it up.

If you actually read the post and followed what was going on, you would have seen that he said he cant get the car past 3900 RPM's when ON THE GAS.

That is why I told him to have a friend see if the throttle plate was fully opening when he "floors the gas pedal"

Originally posted by Star Turbo Talon
Factory Throttlebody should have the throttle plates fully closed at idle. Apparently we have a lot of people on the site that have never looked at their throttlebody before they screwed it up.

????

this is kinda old but a lil update and some more questions from me. i got the not being up to rev past 3900 rpms problem fixed via spark plugs. then the car couldnt keep a steady idle. id have to constantly stay on the gas to keep the car running when first started. it would die in the middle of shifting gears. but after some warm up, it would keep its idle fine. i took the car to autozone for some diagnosis and it came back as one of the iac codes as well as tps codes. so i got a new iac from daes and the car now idles fine. but its climbing to 2000 rpms when startup and then dropping to 1400-1500 range. the throttle plate is fully closed and there is no tension in throttle cable that would keep it open more than normal. is this a faulty tps symptom?

you may have to adjust the pintle on your IAC - un screw it a half turn at a time until you find a happy idle.

another symptom i forgot to mention is that ill be driving say in 1st, bring it to 3000, push the clutch in bring the rpms down, which they do, and then even with the clutch still in it begins climbing. i guess thats the same as the idle problem. also, ill put it in a gear, and without any gas, it seems as tho the car is accelerating by itself.

ill get at that iac tomorrow. thanks.