Intermitent Lockup Problem.
 

I've got an issue with my torque converter locking up that I'm trying to diagnose. I've got a 1988 IROC with the L98 and 700r4 from bowtie overdrives with one of their 2,400rpm stall converters.

I've had this setup in my car for 3 years and lockup was working fine until about a month ago. After starting the car when it's cold lock up works fine until about 10-15min then it won't lock up at all. Could it be a loose electrical connection or something in the converter itself? I'm not getting any check engine lights either.

Re: Intermitent Lockup Problem.
 

While driving take your left foot and pull up on the brake pedal. Lockup kicks off when brakes are applied, sometimes switches go bad.

Re: Intermitent Lockup Problem.
 

Thanks I'll check that out.

Re: Intermitent Lockup Problem.
 

There is a terminal in the diagnostic connector that locks the TCC if you ground it. I have a problem with my TCC not locking all the time, but it always does when i ground the TCC terminal in the ALDL, so that's how i found out it was a ecu problem.

Re: Intermitent Lockup Problem.
 

I worked on my car yesterday. The throttle position sensor isn't working properly because the metal tab that rides on the throttle blade was broken. Computer has no idea if the throttle is open or closed so that's part of the problem. I ordered another TPS so hopefully I'll be able to eliminate that variable as part of the problem.

I'll check out that TCC diagnostic and see if that works out. I've had better luck with AC/Delco computers in the past. I'm using an ECU from NAPA now and that may be part of the problem too.