1995 k1500, 5.7/350. Backfires through intake

[RhettR7707]

Oh yeah, you'll want to rectify that with a heated unit. If all you see is one wire going to it, it's a non-heated type. Either way, you'll definitely want to get a scanner and see what it's doing.

I've heard O2 sensor cross counts should be 20 or greater. The unit in my truck reports 6 at best. As a result, I sometimes get the error code for "Lean limit reached."

I see. Unfortunately, it does look like I've already got a heated sensor, based off of it having 3 wires. I do have a buddy that has a scanner for obd-I. I'll have him hook it up to see how it's looking. Do you think it could possibly be a timing issue? Thanks

 

[Schurkey]

There's a dozen things it "could" be.

Verify fuel pressure and a decent spray pattern from the two injectors.

Connect a scan tool, verify ALL the sensors, and ALL the computer outputs including but not limited to electronic spark advance, EGR system operation, EVAP system, etc.

Check all the normal "tune-up" items. Distributor cap, rotor, plug wires, spark plugs. Test the spark power using a spark-tester calibrated for HEI. Check the PCV system. Look at the magnet on the distributor shaft--they're often cracked on TBI distributors.

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And I'd want to know that all the valves open and close like they're supposed to, and when they're closed, they actually seal.

A leaking intake valve, or an exhaust valve that doesn't open can each cause intake-manifold backfiring.