terrible miss/backfire

[blazinman08]

whe i am driving it backfires through the throttle body and loses power i cannot figure this out could this just be fouled out spark plugs

[old_master]

Year, make, model, engine, 8th character of VIN, what's been done to the vehicle as far as repairs, SES light on? What DTC's are stored? We need more information to help you.

[blazinman08]

it is a 89 s10 blazer 4wd 4.3 L fuel injected replaced fuel filter,coil,spark plugs and wires, distrubtor cap and rotor

[blazinman08]

can some one please help

[old_master]

Induction, (backfire through the intake), can be caused by incorrect valve timing, incorrect ignition timing, excessively lean fuel mixture, or incorrect secondary ignition wiring. Check the easy stuff first: ignition timing, plug wires correctly in the distributor cap, (firing order), and fuel pressure.

[blazinman08]

i checked the firing order that is correct now how do you check ignition timing

[old_master]

Behind the carpet, under the glove box, next to the firewall, there is a single wire with a connector, unplug it and check ignition timing with a timing light. Sticker under the hood should give the spec.