Can a TPS problem cause surging

TbirdSCFan

Registered User
Anyone have this happen? I'm running out of things to try. My problem is this. Under boost, I get this surging that seems like fuel starvation. Around 8-10 lbs, power will start cutting out and there will be a sort of surging. Boost guage will bounce up to 13 lbs and back. I suspect when its doing that, there is a bit of preignition pushing gas/fuel back into the intake (a backfire if you will, minus the KaPow).

Here's what I've done to try and fix the problem:

KOEO/KOER codes, cylinder balance test all come up clean.
Swapped over DIS.. no change
Disconnected CAM sensor.. no change
Checked wiring and connections.. unplugged, replugged everything.. no change
Check engine ground straps, ran separate ground wire.. no change
Pulled SPOUT plug to fix timing at 10deg and eliminate the knock sensor.. no change
Checked condition of engine mounts.. no problems.
Swapped out fuel filter.. no change
New fuel pressure regulator.. no change
Resealed IC tubes and SC top.. no change
Checked vacuum hoses (found 1 problem, fixed it)... no change
Swapped MAFs.. no change.
Tested coil pack resistance.. all within specs
Tested/reseated plug wires (one bad.. replaced it). Improvement for a while, but problem came back.
Replaced high mileage plugs. Same result as with the wires.

The problem doesn't appear until the engine has started to warm up. That is for the first 3-4 minutes it runs well w/o the problem. Once its warmed up it seems to get worse.

My next attempt will be to run w/o the TPS connected, swap out the EEC (i have a spare for this purpose) and possibly the fuel pump. I have not run with a pressure guage connected to the fuel rail. I don't believe this is an injector problem or else there would be problems at different engine speeds.

I don't think its transmision slippage since it happens under a variety of clutch engagements (i.e. fwd only, fwd+intermediate, direct, direct+band).
 
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I know you're all dying to know what the resolution of this problem was. Well turns out it was the plug wires :rolleyes: after all.

After replacing almost everything including the original plug wires that tested bad, o2 sensors, coil pack, and wiring harness, I went ahead and put on a brand new set of plug wires.. problem solved! :rolleyes:
 
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