LukeBlizz

Hey folks kinda new to the forum, been reading for a long time just n ever posted, my problem is my idle will drop down and hold around 1500 to 1800 rpm for a couple seconds then drop down to idle speed. ive cleaned the IAC and the throttle body and still has the idle poblem. anyone ran into this problem before, thanks

dawson1112

Could you explain with a little more detail?
what do you mean it will drop down to 1500-1800?
When does it do this , and for how long?
Its normal for the engine to rev up to about 2k when first started for a few seconds the as it gets going drop down to normal idle of about 850 rpm.
It is also normal when you come to a stop and push the clutch in for it to idle high for a second.

LukeBlizz

if i drive it , when i stop at a light or stop sign the rpms will drop down to around 1500 and hold there for a couple secs then drop off to 850. or if i rev it up it does the same thing.i can tach it up to 4grand or whatever and it will drop right off to 1500 to 1800 hold for a couple sec then drop right off to 850

dawson1112

You may need to check the TPS voltage, and then do a idle relearn on it. Maybe even clean your MAF

Honestly as long as it doesn't hold there for 15 or 20 seconds and its only a second or 2 It is pretty normal.

88horserider

Im having issues with my car cutting off on me when i go in on the clutch, i see you mentioned doing a idle relearn..... could you elaborate on how to do that if you dont mind please.

LukeBlizz

i, going to try that on my next off day i was talking to a guy here at work and he said try that also, its probably longer thatn a couple seconds. it just dont seem normal. all the other ones i had never done that. thanks man for the help

90_Mustang_GT

get yourself a multimeter and check the resistance values of car at idle, .90 give or take +/- a few is where ya wanna be at idle. with test leads hooked up rev your car up and watch the numbers rise and fall see if they do this with a smooth transition, any spikes or hangups and the tps is bad. to get the tps at a good point at idle, have to oblong the holes out with a drill so you can spin the tps until voltage is set accordingly. the MAF can be checked the same exact way, to watch how the numbers rise and fall, needs to happen smoothly. What is your timing set at?