hmmm well what do you have the boost set at as compared to what you are actualy reading. i know when my buddy added his exhaust he developed a mean case of creeping boost but that also was due to a weak inner blow of valve. he had top send the piping back and they reworked his and now the bitch holds a constant 9 pounds i know thats not alot but we are talking about a stock tacoma motor here.

you could always drop the back section of the exhaust and take it for a spin that way you can see if that is whats holding it up. on a side note i talked to jeremy the other day and he said he is going to go change the plugs on his sy and then maybe hit the streets this weekend for a little awd drive action. well good luck with finding out the problem.