Fixed IDLE surging, hunting on my 95gt Stang

calitower

New Member
Dec 31, 2003
16
0
0
I have a 95GT 5sp, daily driver that's heavily modified, and always run like crap. I'm one of those guys that buys stuff here there and then when I got a bunch of mods I slap them on.
I had bought GT-40 heads, intake, E303 cam, 65mmTB, 75mm Pro-M MAF, bbk CAI, MAC (crap) eq. sht headers, pro-chamber (way too loud) catback (BTW..MAC and "True-Fit" hogwash. I got stories over them but I'll save them for now.) and some other small goodies. One day I convinced by buddy to help me tear into it. When we were done, the car idled like crap..ran rough, hunted, all the SN95 probs. I took it and had it dyno'd and tuned by www.racesystems.com. After, it ran better but still hunted and, high rev stick during shifting. I started calling FMS, pro flow, heard 400 diff things to check....everything looked good. So I thought the fix would be to drop in a powerdyne. No change, thing ran like crap still....back to the dyno and more tuning...again, ran better but still hunted, high revs and friggen surging (traffic/surge * rpm = jerk)
I was starting to really hate my car over the way it was driving. I was considering buying one of those STI's or EVO's and letting the stang rest. I decided to buy another fms 65mm TB thinking it was some how leaking. However, with the new tb installed it still ran like you know.
I hit the web surfing and stumbled across this site and started reading all the articles about idle issues...surging, hunting, high revs when coasting..during shifting etc. After reading about 30 some posts with issues like this I came up with a list of events. 1) everyone had atleast a k&n or more. 2) the problem would start to happen after something was done to the car...whether it be a K&N filter/clean or intake work, 3) it always involved taking out something in the air intake passage. I figured that chances are pretty slim that something goes wrong with the TB electronics...maybe the TPS needs adjusting if it was out. I determined that I had vacuum leak somewhere. I looked at the flange on the MAF to adapter piece for elbow to air filter. I could see the rubber gasket in between the flanges was cracking a little. I took it apart and found a totally warped up looks like it got too hot rubber gasket. I made a new one and put it back together. The car runs AWESOME...idles at 700rpm, no hunting, surging...I also got 2psi more out of the sc.
I tell you....if you have this problem after you did "something" to your car...before turning all the screws on sensors/stops and replacing them...look for a vacuum leak. It could be anywhere from the K&N not seated 100% or hose clamp not tightened 100% to a gasket not giving 100% coverage causing a leak. Also if you play with the idle set screw (one on passenger side) this will not only open/close the butterfly plate but also changes the TPS value. And the IAC..DON’T Clean it with carb cleaner…you’ll kill it off permanently.One more thing..if you cleaned the k&n it could have sent oil over the MAF sensor…clean it..atleast check it.
Not bad for a New Years Day feel....
 
  • Sponsors (?)


Welcome to SN. We're all a bunch of freaks in here, but we don't bite (much).

Glad to hear you hung in there and got it running right. Much better than giving up and buying a 4-banger, even a turbo one ... :D

Dave
 
Great Post...My 92' had the same problem and after surgically going through every little thing the only thing that fixed it was it getting totaled and me buying another car...Glad to see you fixed yours I know how irritating that problem can be. Welcome to SN :nice: