Y'know, this thread just made me think of something.
Early this spring, I was on my way back to college at Penn State (in central PA) after visiting my family in Philly. After about 3 hours of steady highway driving (I'd say a consistent 75-80mph), I was going up into the mountains when my MSP started having .. seizures, I guess I'd call them.
I was going up the largest incline of the trip -- 18 wheelers are restricted to the right-hand lane and can barely manage 20mph, to give perspective -- and pushing on the gas to maintain the speed I was at before the incline. I was boosting, but NOT much -- I'd guess around 4psi, MAYBE 5psi. About halfway up the mountain, my car started bucking like mad. I had to ease on and off the gas to make it to the top. Once there, I pulled over to check things -- all hoses fine, everything looked fine, WTF. Got back in the MSP and continued driving.
I got back to my college about a half hour later, let the car rest for about an hour, and then went to drive to Wal-Mart. On the way to Wal-Mart, the bucking started again, I got a CEL, and I once again pulled over to check under the hood. STILL nothing. I drove the rest of the way to Wal-Mart very carefully, with the CEL still on, listening carefully to try to figure out what was going on. Got to Wal-Mart -- still completely puzzled.
Came out of Wal-Mart @ 20 minutes later. Started my MSP. CEL was gone, and the car drove perfectly normal. Or at least as normal as we ever get, haha.
I have the MAM SRI, MAM FMIC, Greddy Type-RS BOV, relocated MAF to boosted pipes, and a custom cat-back exhaust. That was THE only incident I've ever had like that with my MSP, though I've mildly boosted in 5th gear plenty of times before.
Maybe it was the additional stress that the mountain incline produced? s*** if I know.