wildsurfer92

okay guys, i got an 87 lx vert im working on for a friend, and he has an idle problem...he just did plugs, wires, cap rotor, and oil change, and he just put on a new to his car throttle body off of another mustang, not sure what year or anything..the car is all stock..now he is idling at like 1500 rpms, and it will like surge up to 2000, and stay there for a while...i turned the throttle stop screw back because it was in very far, and that helped a little, but i am out of ideas, any help!?

1992lx5.0

ok you should never have to touch the set screw, and why is the throttle soo high... is this car MAF or speed density

1992lx5.0

i am assuming it is a maf car...if this is the case check the tps voltage it should be about .97 -.99....then check the timing...dont forget to pull the pill to readjust if this is the case...your baseline timing is 10 deg, i run my car between 12-14, imo. if this is not the problem check the cold start sensor on the driverside lower intake mainifold, take it out and replace that, this can cause it to run high idel tricking the computer telling its cold when its really not....thats just to name a few things to start...

then look at this link and it wil tell you how to readjust it
http://sbftech.com/index.php/topic,1031

wildsurfer92

okay sorry the car is speed density being a stock 87 correct? i only adjusted the screw because that throttle body had been off the car, and it was all out of whack, and cranked in a good deal...i tried to mess with the tps, but there doesnt seem to be any play in the sensor for me to move it...

Joel5.0

DIY KOEO/KOER/Cylinder Balance Self-Test
Summarized Base Idle Reset Procedure

LUK

cholericfc

Yeah... make sure you do all the steps in that "Idle Setting procedure" and do them in order.....

Here's a less confusing procedure thats the same damn thing:

http://www.freewebs.com/vristang/idl...20-%20FRPP.pdf

This is straight directions from Ford. Keep doing this procedure until it corrects the idle.

wildsurfer92

is that idle setting procedure the same for maf, and speed density? i did the steps today, and still no luck...with the iac disconnected, i could only get the idle down to like 850-900 the screw wasnt even touching anymore...i have no clue whats wrong

Joel5.0

The one I posted..... yep.... TPS setting is NOT required as long as it falls within specs. From the symptom you're describing, you could have a faulty IAC valve (stuck partially open), a big vacuum leak, or a TB blade linkage not closing all the way.

dudeboy

cholericfc,
I hosted that image FOR YOUout of good faith. I will not be part of spreading WRONG information.

If you want to post this image, then you need to host it yourself!!!!!!!
Please don't link to this again.

Photobucket is free, learn it!




Now,
there is a lengthy discussion on why the tps does not need to be set to .98v to .99v........
https://mustangforums.com/m_4613249/tm.htm

However,
If you want to try following the procedure linked to by cholercfc, then please follow it to the letter, and come back and tell us how it works for fixing your idle problems.... [&:]
LUK,

jason