Help!!!! backfireing problem
 

I have a 88 chey blazer k5,, i'm having a problem with it backfireing when i step on the gas and it is also running alittle rough.. i change the spark plug, wires, distributor cap, coil, adjusted the timeing, change the fuel fliter and rotor...... i can't think of anything else to do .... can anyone help.. thank you,
raylene:icon_hyper:

What did you set the timing at? Or did you just rotate the distributor on a whim?

check the timing on the crank or could be needing a valve job

i did the timing light on it!!!

I am assuming that you have the TBI 350 here...

To set the base timing on this motor, you must first disconnect the 'set timing' connector (tan/black wire close to the distributor). The engine should be up to normal operating temperature and the A/C set to 'off'. The transmission should be in neutral and the wheels chocked.

Set it to 0* to the #1 cylinder.

The crucial step here is to disconnect the 'set timing' connector.

yes i set it to 0....

and i try move the distributor

check your plug wires and make sure they are on the proper plugs. small blocks will idle quite nicely with the two rear passenger side plug wires swapped but backfire under load .

I had a similar problem... ended up being a flat cam lobe, so maybe look that direction.