I had an issue with my 22re and I bought a rebuilt motor for it, ran fine and started having problems again and turns out the shop messed up the timing chain so it bent 3 valves in the head. Took the head to a buddy of mine who works on these motors and he rebuilt the head for me. After reinstalling the head I am getting a weird "popping" noise comming out of the exhaust as if it were a sucked valve? I readjusted the valves thinking they were too tight but it is still having the same symptoms? Any help would be appreciated.

Thanks in advance

 

an after-fire? I had an after-fire because my TPS was misadjusted. But I read online it could also be caused by an improper air/fuel mixture.

 

What types of things could cause this improper air/fuel mixture?

 

And since were here, how does one adjust the air-fuel mixture?

 

You can adjust the little gear in the VAFM box (do a search for that) but I wouldn't recommend it. I believe the computer should do the corrections if the mixture is incorrect. So most people don't recommend messing with this.

if toyotas are anything like our 96 subaru, a bad O2 sensor can cause a bad mixture. Or even a bad sparkplug/spark. But this is our subaru, not a 22re.