threehourshower

I tried searching first, many places on the internet. But I cant seem to figure out what my issue is. I have had this 95 5.0 vert gt for about a month now, and It has seen the shop already, but I cant afford to keep putting the car in the shop. They keep finding other issues, not whats causing my misfire. And thats my problem, a misfire. It only happens at low RPM under load (between 800 and 1500), mildly at idle (enough to make the car shake), and very severely when I let off the gas and let the car coast. The temperature seems to have an effect on how violent the misfire is, but not really too much. I have already replaced the plugs, plug wires, and the ignition coil. They needed replacing anyway. The car was NOT doing any of this when i picked it up. I attribute it to something electrical because the battery voltmeter dips slightly with every misfire. At this point, I have to question what I know about alternators... could that be my problem? There is no CEL. Wires have asbestos sleeves at the boots to protect them from my headers. Misfire is not constant, but at idle it will happen about every 2 seconds. Any leads on my problem or how to find it are GREATLY appreciated.

GT Nate

IAC valve could be bad (idle air control valve)
EGR valve clogged? EGR tube clogged?
Throttle position sensor (doubt it's that)
MAF sensor, or tear/rip in air intake tubing? They sell MAF cleaner...

Just thoughts....
Good luck

threehourshower

MAF is brand new as well, that was one of the things the shop measured to be bad. Intake is solid, no leaks there (aftermarket). IAC was on my list of possible culprits as well. The EGR has been deleted I believe, along with all the other expected mods like headers, exhaust, mild cam, etc. Has a BAMA performance 4 bank eliminator tuner, but Ive been running on stock and switching tunes seems to have no effect on the misfire.

pure_kaos

O2 sensor(s)?

imp

Distributor cap, hairline crack, moisture enters crack when present, shorts high voltage to ground, base of distributor. You did not mention cap, so I gather it was not replaced. Try a new cap and rotor, let us know.....imp

GT Nate

check the points too... they can get a white buildup on them. I do not think you can put an electronic distributor on it.. (I know I couldn't on my 93 TBird 5.0)

threehourshower

Ok guys I'll give that a look next time the car is cool and I have some time. I noticed today that in drive, at a stop, the battery gauge has started to dip really low, around 10v or so maybe less, and stay until I get going or shift to neutral, at which time the gauge will slowly climb again. Pretty sure the battery is fairly new, strong enough to keep a radio on all night, and I just put a new alternator in yesterday. Dist cap does make sense to be next thing to look at, maybe timing is messed up.

ZEN357

Since it's a 95 I assume it has a 302 with a distributor, have you tried replacing the distributor? Here are some options for you.....

https://www.jegs.com/webapp/wcs/stor...ersistYmm=true

Derf00

Points....

....as in points and condenser ignition? Wrong era dude

I don't think you'll find any vehicles with that system after about the mid 70's except for VW beetles/buses from Mexico.

wbrockstar

Your year model came with a 130amp alternator from the factory, so there's no reason your amp gauge should be reading that low,unless youve got some sort of charging/battery/ground/cable issue.I would
check your ground cables/wires first.There are 3 main grounds.The neg battery cable is the power ground for your starter & alternator.Someone else will have to post the locations for the secondary (engine to body) ground & the eec ground (for the computer)
On the Foxbody,the grounds are:
1)Neg battery to engine block- 4ga cable
2)Intake to driver firewall- flat ground strap
3)Neg battery to driver fender apron and apron to black connector which plugs into a matching connector at the main eec harness- 10ga wire.
The locations appear to be different on the SN95 models though and Ive seen different locations listed between members so maybe someone can post a accurate picture of each ground (3 of them) for the 94-95 model to make things clear for once.

After you check that,I would make a trip to your local parts store and get your battery and alternator tested.They can both be tested while they're still installed.Proper voltage is imperative for a EFI car,so an issue with the battery,charging system or grounds can definitely affect how the engine runs.Battery voltage is really important for proper fuel pump output.Low voltage can affect pump pressure