weird boost after hot on long trip

[Jholl]

so I took my 01 gtp with on a 3 hour trip to Muskegon last weekend and noticed something a bit weird, that after a few hours on the road and need to pick up speed or climb a hill it creates boost and almost hesitates in high gear 3,4, and does it with low boost pressuse. its hard to explain but has a back and forth hesitation until you create more boost pressure and smooths out a bit. car did this on a 5 hour trip to traverse city but didn't think much of it,until now. only had the car for about a month has 140,000 miles replaced the fuel pump, water pump, trans, and engine oil/filters, catless downpipe, supercharger oil. had new plugs/wires when bought, wondering if its the coupler? but I have been driving the hell out of it put almost 3000 miles on it and it runs and drives great love the car but want to see if anyone else had this problem? thanks -Jordan

[QUICKSILVER462]

Sounds like TCC oscillation, very common to these cars. Next time when that happen, let off the throttle to unlock the TCC and then re-accelerate to your desire. OR, you can push the throttle down farther to make it downshift and unlock the TCC. The TCC in these car is designed to have a continuous small amount of slip at all times for smoothness. The problem is wear on the TCC valve in the valve body, there are upgrade kits on the aftermarket to solve the problem. Or you can band aid the problem by tuning it out, it will stop 99% of the issue, but may not be an option if you don't already have tuning software.

[BillBoost37]

When was the last tune up etc? Often this behavior is ignition or intake cleaning related. I like to rule that out before saying oscillation. Only because I have seen simple maintenance often fix this type of issue.

[Turbocharged400sbc]

make sure you do not have the lower part of your boost bypass valve cap off or blocked in any way
I have seen something similar on a car where the trapped air would heat up and hold the boost bypass valve slightly open and it would oscillate.

[Jholl]

the tune up is fresh, I don't have tuning software was going to wait until I got my plog on, and some other things, and then got to figure out how to get it tuned and all that worked out. but where is the bypass valve located? is it with the bypass solenoid? sorry im new to the gtps