Surging on my 87 Mustang 5.0
 

when the car is idle, the motor surges...what could this be??



Dark_5.0 ---- well haven't done anything to my 87 yet...just bought the car last weekend.....so I'm working on upgrading, hopefully I can save enough cash flow to rebuild this motor and make it a BEAST :D !!!! order some BBK short headers for it but waiting on exhaust till I put the motor into my 64....any hints to make the motor a beast would be helpful!! thanks!!

The TPS, Throttle Position Sensor went bad on my '89, which caused erratic idle. Replacement cured the problem.

There are other things that could also cause it, but checking the TPS may be your first step.

This happened to my stang when I replaced my upper intake. There is a little part from Ford (I don't remember the part number) but it goes between your Idle Air Control Valve and the TB. It acts as a spacer. There are two screws that you can turn with an allen wrench to adjust the idle speed. It cost me 25-30 bucks. This may help...

Probably the TPS. but it could also be a vacuum leak.

I would start wih the TPS as stated above.

Have any mods on your speed density stang???

Later.