'94 3.0 Backfires!

[delinquent]

Hi, I have a '94 3.0 (Mitsu) Caravan w/ 156K on it. Recently it has been backfiring only at about 3/4 to open throttle..I'm thinking maybe injectors, but I am not sure. I will probably bring it to a dealership (if free or cheap to do) and have them plug it in and see what the problem is so I don't just go out and start replacing everything, also some injector cleaner will probably help as well.

Any suggestions?

Thanks,
Del

[capoeta]

autozone will check (scan) your vehicle for free if you have a "check engine" light on.

most shops charge $100 minimum to do diagnostics on vehicles.. (that's how much I was charged)

[lakeman]

Sounds like it may be running lean..have you replaced the O2 sensor(s) ?. Also check fuel pump pressure and regulator.

[slantsixness]

Define "backfire" throught the aircleaner, or the tail pipe?

Throught the air cleaner:
Fuel delivery problem Clean injectors and throttle valve. then see what else comes up (codes)

Through the tail pipe?
O2 sensor, clogged catalytic convertor, burnt valve(s), worn cam, blown headgasket (would overheat too)


However, if you just recently filled the gas tank and it started this, Bad gas will cause it to backfire (low octane, crud it in, etc.

Hope this helped, mine doesn't like cheap (East Coast, Racetrac) gas stations. Might be your trouble too.

Slantsixness

[delinquent]

Just replaced both MAP and O2 sensors, gave it a tune up and it runs great now, was not getting good enough spark.