Engine Mechanical problem
1989 Pontiac Lemans 4 cyl Front Wheel Drive Manual 80000 miles
I just started working on this car it is a 2.0 GSE I was told that 4 of the valves were bent and I have 4 new ones, so the first thing I did was reset the mechanical timing because it was off, and I turned it over by hand a few times and started it. It will run and back fire and shoot flames through the throttle body and won't rev past 2.5-3k rpms before it starts pushing back at the throttle body and starts backfiring, I had it catch fire a few times- I played with the distributor with no luck and I redid the timing again today and now it runs worse, maybe im not lining something up right or im not totally top dead center, I never pulled the valve cover to redo the timing.
also one of the rocker arms on this car is slightly differs from the rest, it's slightly bulkier than the rest.
any help would be much appreciated and I can relay some more info if you guys need it thanks.