Car runs like crap after hard shift

[Lucas03es]

So my friend had disconnected his battery when I was replacing his ISC. The car had been sitting for a couple weeks beforehand and I do not know if the car had the same problem before. We reconnected his battery and drove the car a bit and did some pulls. The car ran and drove fine when I was driving, but when he drove on the freeway shifting from third to fourth he had a really hard shift, idk if it is his fault or the cars. The CEL turned on and the car lost all power, and made sputtering noises (misfire possibly?). The car also feels like the clutch is stuttering like you don't give it enough gas when you take off and/or shift. I was looking at his AFRs when we were driving nd they were all over the place. He also said the CEL came on when the bov hit.

The problem also dissappeared completely when I disconnect and reconnect the battery. Any ideas?

 

[boostedjay32]

drive it around again... the code will come back on.. scan it and see what code you get.

 

[tjbiker031]

scan for codes, check for boost leaks

 

[tma1c]

scan for codes, check for boost leaks

+1 i would check for boost leak.

 

[95redturboawd]

Is the bov recirculated?

 

[92GSXtacy]

Re-circ the BOV. If it's VTA and you're running a Mitsu MAF all you're doing is flooding the engine with fuel in between shifts. Eventually you'll foul out the plugs and have a mis-fire issue.

If your BOV is re-circ'd I agree with driving it around until it shows up again then scanning.

 

[Lucas03es]

The bov is recirculated. Could a boost leak really just suddenly occur once the ECU is reset and go away once I reconnect the battery? The car is a 97 gst with ECMlink, COP ignition, and a greddy type-rs bov if it matters at all.