I know its a different car but all you guys here are the cats *** so i figure id get some good info here......

I got my truck tuned (colorado) a few weeks ago and the trans is acting a little weird. He said all he did was bump up the line pressure but now if im cruising at like 15mph in 3nd gear it goes into lock-up and when i hit the gas it stays in lock-up. Doesnt matter if i hit the brakes or not. I have to put it to the floor to hit passing gear or come to a stop and let the trans "re start". Why is my trans staying in lock-up? Does it maby 2 times a week, so not very often. And how high can you go on line pressure on these? (4l60) I dont know where mine is but i want it to shift real firm/hard. Im going to meet up with my tuner in a few weeks so the more info the better. Hes using HP Tuners also and tuning my truck while i drive it.

 

First IMO Using tuning to get really firm shifts by raising the line is not the best way to accomplish this. If you want really firm shifts you should invest in a shift kit like transgo.
On yourlockup and no downshift issue if it occurred imediatly after tuning, Then that where I would look, However it being intermitant is strange. I would get back to the tuner and have him look at sensor data too TPS etc.

 

ok, i know im not going to get shifts like a race car and it is my DD so ill leave it where its at. And yes, it is pretty intermitant and it did it maby a week after i got it tuned and just did it last night driving down a side street. You hit the gas and it kinda bogs down and stays at a real low rpm. So maby its not stuck in lock up but maby staying in 3/4th gear and not down shifting. What are some specs i should have him look at or where should he start. He doesnt own a shop but he does tuning on the side so im pretty sure hes not perfect at it.

 

I would watch the TPS (THROTTLE POSITION SENSOR) operation. He should know how to do that with the HP