Recently replaced my blow off valve with a new scarles one, discovered that the old one was sucking in air at idle cause if my car to run at 11 in vacuum according to the gauge. It’s now at 20-23 in vacuum at idle etc now.
I took it forbits first test run tonight since doing some maintenance and have found that it’s not boost right, it picks up boost well and then once it hits its peak the boost drops to about 2 psi (standard 4/5psi tune). The car seems to shudder and lurch about occasionally surging back up and down, a couple of times it had a slight backfire. Temp is normal. No smoke. No lights showing up or anything to show that it’s picking up an error.
Has anybody had this issue before ?