Never ending TCC mystery problem (4l80e)

[Schurkey]

When my '88 was misfiring on 1 and 3, it was because someone screwed the pooch by installing the wrong intake manifold gaskets. The gaskets distorted, which opened up an air leak into those cylinders.

Some days, I need to sit myself down and have a stern conversation with me.

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[Supercharged111]

I too have been known to be my own worst enemy. He could spray carb cleaner around the intake base, but that would only reveal an external leak. Since intake gaskets are a known failure point, that's an excellent place to look.

 

[Boostvalve67]

Alsp remember if the tuner has the unlock tuned for to sensitive of a map signal reference it might be doing what it's told. I'm leaning towards manifold gaskets myself but faulty maf / map will screw with you and not set a code. Anything that senses load can get you. Will it re engage on lift throttle? Will it stay locked if you are in manual 3?

 

[Nad_Yvalhosert]

Isn't there something about the PWM solenoid having to do with the TCC?

What's the history with the transmission? And the truck? Did the problem develop after you started ownership? Or it's been like that since you you bought it?

I don't know enough on how these units work. Maybe a valve is sticking in it's bore? There's also a little tiny screen somewhere on the valve body that I think can get clogged with debris.

I admit, I'm much less informed regarding the trans operation of the 4L80... when did GM begin to PWM the trannys? '95 with the 4L60s I knew...but 4L80?
I ask because I'm looking to purchase a '95 2500 Chassis Cab. Is that gonna be a unicorn: OBD1 5.7 TBI, but 1st year PWM'd tranny?

OP what does the datalog of misfire history again? Mostly 1&3?
Check for intake gasket leaks

 

[stutaeng]

I admit, I'm much less informed regarding the trans operation of the 4L80... when did GM begin to PWM the trannys? '95 with the 4L60s I knew...but 4L80?
I ask because I'm looking to purchase a '95 2500 Chassis Cab. Is that gonna be a unicorn: OBD1 5.7 TBI, but 1st year PWM'd tranny?

OP what does the datalog of misfire history again? Mostly 1&3?
Check for intake gasket leaks

4L80e were all PWM. The TBI/4L80e did have a unique ECU if I recall. But I'm no expert on TBIs.