motorman524

When I push the throttle and let off it hesitates then revs. It is worse when it is warm. It has done this forever and I can't find the problem. Also, the car starts fine when cold but when warm sometimes I have to push the gas to start and sometimes I don't.

The NGS only pulls up emissions codes because I deleted all that...

http://www.youtube.com/watch?v=Q-lfF34QDaM

rcdblink716

tps? use that ngs to look at some pids like tps voltage fuel trim. go from there

motorman524

tps is new and set at correct voltage.

rcdblink716

is reference voltage at tps good? first thing to check before installing tps. and don't take this the wrong way cause i'm not trying to be an *** but there is a such thing as bad new replacement parts. Don't always assume a new part is not good. Just FYI, wish someone had told me this, I have made that mistake.

A little aside. I had a 73 351 cleveland mustang show up today. Wouldn't run. No fuel. T Customer took it to a hack who replaced the pump, lines, sending unit and carbeurator. He replaced the pump first, assumed it was not the cause since it was new. Guess what i was putting on the car at 9 am? Drove great

motorman524

how do I check reference voltage? what is that??

rcdblink716

tps uses a 5 volt reference supplied by the pcm. it is 3 wire, one is reference voltage, another is ground, and the third is signal return. if there is a dead spot in the tps right off idle it could cause that hesitation

rcdblink716

check that u have 5 volts at the tps connector. get a diagram to tell u which wire or just check all three. usually easy to figure out. I have a feeling this is not ur issue though since you were able to get tps voltage set correctly and ref voltage is supplied to other sensors via same circuit like MAF. unless there was an issue in the particular wiree that goes to the tps. you can scope the tps to make sure there is no dead spot in it but i would deffinitely grab that ngs, pull up some pids like tps voltage, fuel trims, o2s etc, and replicate the problem to see if that leads u anywhere.

motorman524

EDIT: n/m I didn't refresh the page. I'll hook up the NGS and give this a shot

Thank you.

rcdblink716

won't hurt anything but i doubt this will fix your problem. I have seen computers make up for some off base idles just fine. just make sure it holds 600 ish rpms with the IAB IAC (whatever u want to call it) disconnected

motorman524

So I called my Dad this morning to barrow his NGS, asked him about pids. He said that the EEC IV system won't show pids, it doesn't have that kind of feedback.