Boost Spike

[Bunta]

Yesterday I took my 1990 eagle talon into the shop to get a custom downpipe for my thermal exhaust. So now it's about 2.5 inches from flange of 02 housing then 3 inch all the way back. Im using a Greddy Profec B-specII Electronic Boost Controller to tune the boost. Yesterday night I turned off the boost controller, floored it and I'm hitting 20psi. I then tune it for normal settings, the car would hit 10psi then all of a sudden it starts to go up and then again up to 20 psi. The car has just the basic bolt ons. The o2 housing and exhaust manifold is still stock. One of my friend is saying it's the crappy o2 housing and that it should either be replaced or ported. Keep in mind this problem didn't happen until after the trip to the shop to get the full exhaust done.

Please help.

Thanks!

[Bunta]

Anyone?