the truck will crank up and idle fine, but as soon as you give it gas it backfired throught the throttle body, and you can't go over like 1 mile an hour, i replaced the plugs, wires, throttle body, cap, rotter button, cleaned the egr valve, blew out the gas lines, changed fuel punp and filter???? 1995 4.3

if its back fire'n through your intake its in the ignition
check to see if the engine is on Top Dead Center then check to see if your roter is hit'n #1 you might be one tooth off
check control mod. in the distributor thay go bad at the drop of a hat

what engine are you working on?

hey matt, wouldn't it idle rough if the timing was off?

the one in my orange dime, i think the cat got stopped up from the foam in the fuel cell and got so clogged that it had to backfire out of the intake, because it had no where else to go

check the fuel pressure when you give it gas. cause you have enough pressure to crank and idle but when you give it gas, it won't have enough to run and that will make it back fire. if that is it, then you will need a fuel pump that will pump a higher pressure.

I've had the same problem and it was my cat that caused what you have going on. I took out my cat and put on true duals and it solved my problem. Now mine sounds like I have a small v8 in it.

yea I kind of missed that part
also as I was typing that I thought about when my fuel injection went bad it would idle fine, but as soon as you gave it gas it would back fire though the intake and it wouldn't build any power.
also I had a ignition modual go bad in the distributor and it would idle but it wouldn't build power it acted like it had a flat cam lobe
K\N air filters don't with stand fire

i had the ignition control moduel checked and it was good, so i am going to do a pressure test and see what i can come up with

Its out of timing, It might not idle that bad. Check that first before you put more $$$$ in it. My old truck did the samething.

checked the timing and it was good, so i dont have a clue

you can check your fuel pressure
turn your key on and you'll hear the pump come on and go off (it only takes a couple of seconds to pressure up )then at the valve stem deal on the back side of your intake manifold push that with a pen,a screwdriver, or what ever if it blows gas every where you got fuel if it only trickles out there you go
Its not accuret but its effective


is your engine a vortec if so I'd pull the plenom off your intake and check your injecters and see if one has sprung a leak
if one is leaking or if your fuel regulator is leaking it will blow gas all over in the plenom and it will Idle fine untill you give it gas then it will drop cylinders fowl plugs and run like shot

I know I've had this problem and I wish I was there it would make it a lot easyer give me your phone # and I'll call ya

you can give me a call @ 770-313-3543

well did it run for you last night

hey after I talked with you some thing came to mind change your dist. cap back to your old one and try that . every now an then I get a bad one (how many times you think its been droped before you bought it)

what do you mean droped?