Car bucking randomly HELP!

Yellow302

Member
Mar 2, 2003
789
2
19
NJ
Car has started to act up lately and I don.t know why.

symptoms are bucking but no backfiring. random rpm. Seems to be fine if i free rev the car.

So far I have checked the following.

Cap- new
Rotor -new
Coil - swaped
TFI or ICM - swaped
O/2's - New (does the same when i shut them off)
Dizzy - Cleaned out with electric cleaner*** running 80% better now, still bucks though.

Things to check still:
Clean Maf
PIP sensor
Dizzy
 
"According to Ford, TFI failure causes the vehicle to buck, hesitate, and experience other "driveability" symptoms that provide a warning that the TFI module is about to fail."

Found this somewhere, TFI moduals are known to die after high temp exposure, my car has overheated many of times lately, could this have killed the TFI.

If so how/where can i replace it?
 
"According to Ford, TFI failure causes the vehicle to buck, hesitate, and experience other "driveability" symptoms that provide a warning that the TFI module is about to fail."

Found this somewhere, TFI moduals are known to die after high temp exposure, my car has overheated many of times lately, could this have killed the TFI.

If so how/where can i replace it?

Heat was a problem when the TFI (Thin Film Ignition) module was attached to the distributor. The TFI module is now located on the fender wall behind the air intake duct. That's not to say that isn't the problem but I would be inclined to look elsewhere. I'd first clean the MAF sensor and see if that helps. It's located in the air intake duct.
 
I havent cleaned the maf yet, but voltage is consistent and fuel pressure is good. My TFI or ICM was right next to my super charger which does get hot. I have replaced/relocated the unit and problem still exists.
 
A TFI's critical temp is ~257*F. Once they start to degrade, that temp can be greatly lower (moving a bad TFI too a cooler location might not solve your issue). Have the TFI bench tested several times at the parts store.

Pop your cap off and run a magnet around in the dizzy bowl. If you start picking up ferrous material, check the dizzy's bushing and inpect the PIP. If the bushing goes, it often takes the PIP with it. Simply having a dirty PIP can cause slight misses and bucks (almost like having timing too retarded on a carbed car). I clean the bowl out with electrical contact cleaner.

Of course, the MAF cleaning idea was excellent. Do that - it takes 5 mins and is free if you have contact cleaner (which you should). Clean the IAT while you're at it (not to fix anything but just so it's cleaned at the same time as the MAF. I do them at the same time always)

Good luck.
 
Are the plugs/wires new as well?

How about running some fuel system cleaner?

Wires are good, plugs are getting old.

I flooded and blew out the distributer with electric cleaner spray and flushed out dirt/oil/grease/old gasket peices

Car is running about 80% better but still bucks occasionaly. going to check the gap on the plugs or replace them soon.
 
Ok good news i guess, CE light came on when the car was bucking again. Im hoping it saves the code in the memory or something so if i hook up a scanner it can tell me what it is.

Will it save the code?