The car is a 95 mustang GT with 130k miles and an auto trans. In the last year I have replaced the spark plugs, wires, cap and rotor, fuel filter, air filter and O2 sensors, cleaned the MAF sensor. The car idles like crap and will randomly buck while driving it. I have replaced all of the vacuum hoses and can't think of anything else to check, I am out of ideas and tired of messing with it, I'm about to throw in the towel, any ideas? by the way no codes or check engine lights. Thanks in advance.
I'm starting to hate my car!
- Thread starter red95gtconvert
- Start date
I've fixed the bucking problem on my car by replacing the plug wires..... 4 times now. But mine were arcing on the Mac headers (which I finally got rid of) and all is well now. I guess this probably isn't your problem since I don't see headers in your sig. I'd be looking towards the PIP sensor in the distributor, then also check for a vacuum leak at the intake manifold (between the upper and lower). If all that checks-out, try just unplugging the MAF while the car is running. If there is little or no change in the idle then its probably toast. Lastly, have you tried running a cylinder balance test with a code reader? That can help pinpoint a problem cylinder if that is the case. Good luck.
SorsCode
20+ Year Stangneter 
Got multiple things you can try... While the car is running unplug the Idle Air Control Valve and see if the problem gets worse or better... That don't work you Pick-up inside the distributor which could cause your problem.. Also whats your timing sitting at and what octane are you running.
Danny
Danny
Blackened302
Active Member
my bucking was due to a huge exhaust leak--my X-pipe wasn't bolted tight enough. just a thought..
Thanks for the tips so far, I have been all over the engine with starting fluid to check for vacuum leaks and have found none so far. The timing is set @14* and I only run 91 octane through it. The IAC only has a couple thousand miles on it. When driving around sometimes it seems like it is misfiring like crazy at low RPM's.
MLC Stang
Founding Member
red95gtconvert,
With that specific symptom it might be a bad TFI Ignition Module. When they test those to see if they are bad, they test both its low-rpm and high-rpm circuit. It can fail in either or both.
BTW, just in case you don't know, the TFI Module is bolted to the passenger side fenderwell underneath your air intake plumbing. Very hard to get out since the small bolt that holds it in place is recessed and it requires a really thin-walled socket to get at the bolt.
If you unbolt it and take it to an Autozone (think that's the place) they will test it for you for free.
Good luck,
gcomfx.com
Founding Member
Good to hear. Probably the PIP. Mine failed as well. I put in an MSD pro-billit. Probably wasted some money doing that, but it looks good.
The PIP, as Danny mentioned, is where I'd have started too. In the future, try douching the sensor with electrical contact cleaner - this will often alleviate the stumbling for a couple weeks. Also, run a magnet around inside the bowl, noting any ferrous shavings being picked up. This can indicate a failing PIP via a bad dizzy bushing.
Good luck.
Good luck.
I tried using contact cleaner with no luck, strangely enough all of the components inside the distributor looked practicly new, I have only had this car for a year so I don't know its life history. I just just got done making a 6 mile drive around town picking everyone up and it didn't miss a lick. It drives good again, now I need to decide if I should just replace the PIP sensor or just spend the 100 bucks and buy a remanufactured dizzy
Similar threads
