djbfunk

i have an 88 mustang and it ws stolen about a year ago and when i got it back from my insurence corp it would some times loop up and down when it was at idle. and it slowly has gotten worse and worse. this year i put an h-pipe with cats on it so i could go through the smog control tests to insure the vehicle for another year. now the car constantly loopsup and down at idle... it stays at 1000 rpm and it dips down and comes back up to 1000 and it does this over and over untill it dips down so low that the car shuts off. sometimes when i comming to a stop the car just shuts off on me.

the car has a new computer, new injectors, new plug wires, new h-pipe with cats, and no other serious problems.... it went through the smog control tests with flying colors. also the car was put on a scope and there seemed to be no problems.

if anyone has had this problem or has any imformation on this it would be appreciated becaue i've spend some moeny on this already and still the rpoblem isn't fixed.

thank you

mustangjoe87

adjust the idle screw, if thats not enough there is a small hole on the blade of the T-body you can make that a lil bigger if needed.

nemethjames1

could be a iac problem occouring.... make sure tps is set to standerds... and idle screw is set right ... have you ever checked the timing?

djbfunk

i've adjusted the idle screw and that fixes the problem untill i start the car up again and the problem comes back.

djbfunk

also, now when i stick the key in and start it up i have to either pump the gas or run the starter out before it turns over

bobby

TPS, $50

roundman

clean the IAC also when you replace the TPS as this is what controls the idle

djbfunk

i will replace the TPS and we'll seehow that works.

thanks for all the helpful info everyone

nemethjames1

how much are those tps's? i got like 5 of em layin around.... and if you play with the idle screw, make sure you set the tps last... idle screw will effect tps voltage reading... should be around .98

88GT40

Sounds like possible a mixture between vacuum leak and idle screw set too high.
i will get a link in just a minute for you to look at.