Weird misfire issue after head gasket job
Hello people of the volvo 850 forum, i recently replaced the head gasket on my 96 850R the job went well with all cylinders at 125-130 psi in a compression test, but im having an issue where the car is misfiring at high boost (see video) and at idle under load when stopped in drive or reverse. The middling range of rpm and boost is smooth, the misfires aren't constant.
For some context before i replaced the head gasket i was having an issue where the peak boost wasn't being reached but the car wasn't misfiring. I had driven the car like this for quite a while.
The current car's equipment goes as follows. I'm using a kinugawa wastegate actuator with the 14.7 psi spring and the IPD heavy duty bypass valve with the 15-16 psi spring. Everything else in the car is stock.
I have a theory about what it could be. I was thinking that it could be the ECU learning how to correct the air fuel mixture now that it can reach full boost. However ive driven the car for over 1200 miles and the issue hasn't gone away however i havent driven it in the range of rpm and boost that had the misfiring issue.
Idk what it could be id love some help.