I have a 91 Formula 350, today I noticed on heavy accel. the car jerks, and surges, slight pinging even. However this is only under load, in neutral it revs no problem. Car has had plugs and wires and tuned up about 6k ago, no problems since. Just started today? I am thinking TCC is locked up, anyone have any typical test proceedures, or trouble shooting chart? Any other thoughts?

 

No troublecodes? Check your ignition timing if you're hearing some pinging.. Could also be a misfire, even though you've done the tuneup. I'd at least doublecheck. A plugwire could have been burnt on the exhaust, etc.

TCC lockup is very distinct. You would feel it lockup pretty immediately after you go into 2nd gear...it would feel like an extra shift, and the car would feel like it wants to bog down. It would jerk and buck very badly on deceleration at lower rpms---not sure about acceleration. You can at least test if the TCC is capable of being disengaged by driving at a speed when you KNOW it has to be engaged, such as 50 mph or so, and then with your foot still on the gas, lightly hitting the brakes. Not really enough to slow the car down, but enough that your brake lights come on. The revs should come up as the TCC disengages.

 

Great, I appreciate all the input. I am also going to go back to basics, fuel filter, fuel pressure, maf sensor, rechecking cap, wires, etc. it has been pretty rainy here the last week or so, and I have not driven it very much in that time frame.
As i am having problems right off the line, now that I think about it a little more, it is probably not TCC problems. i will repost when I find out more... Thanks again.

Oh yeah, no codes....

 

No problem. If it happens in 1st gear, it can't be TCC. Torque converter lockup can only occur in 2nd through 4th gear....never in 1st.

 

Back to square one. did all the basics, thought I had it licked. Now finding out it only has the problem when it is warm. Possible plugged converter? Not to sure what else it could be if only when warm? Any thoughts?

 

Which "basics" did you do? Everything you listed previously?

A plugged converter....well...I suppose it's possibly, but your symptoms don't seem to match that. For the converter, I'd say if it was plugged, first you'd notice a big loss in power...and it wouldn't want to rev past a certain rpm level due to the exhaust restriction. And the converter would most likely start glowing red hot by this point.

 

Yes, rechecked plugs, cap, no burns, no cracks, replaced filter, pressure checked ok,also checked injectors, no bleed down, also ohmed out ok. maf checked ok, rechecked tps. I am pretty stumped, not sure why it only occurs when warm. Would it be possible bad gas, maybe got a lower octane, and when warm it detonates differently? I am reaching at this point.

 

Have you checked your ignition timing? Considering you mentioned some pinging under heavy acceleration. The only thing I can think of to cause that besides timing might be a lean condition....which, since your fuel pressure, filter, and your injectors are ok....it points to the fuel pump pretty much, if that IS the case....

As far as the bad gas goes....well at this point, I guess anything is worth a shot. Try it..

 

Will try the fuel, and also check the timing. it has been great up until this point though, not sure how the timing would have gotten screwed up, but will check it anyway. In the meantime any thoughts would be great, someone mentioned the knock sensor also.
But again, my major concern is this is when warm only?