Help diagnose misfiring in 5.0L

[schadler]

I just replaced plugs and wires in my 97 5.0L. After a few days of it running great, I now have a slight misfiring, but only at idle, and only when in drive...like sitting still in the driveway in drive. I don't notice any misfiring, bucking, etc while accelerating or cruising. The misfire is only at idle, and only every 10 seconds or so. I checked all plugs and removed wires, checked for resistence, and reinstalled with no change. I checked the engine in the dark for arcing and see nothing.

The only problem I had is I damaged a boot on #4 plug, which caused arcing, a BAD misfire and a flashing check engine light. I replaced that wire, and the misfire and CEL went away, but I had a sulfur smell. In an earlier post I did on this topic, some said a flashing CEL and sulfur smell usually meant damage to the Catalytic conv. So I'm wondering if the 2 are related.

I also have an increasing tapping sound on acceleration...sounds like a mild exhaust leak. Could this be related?

Thanks!!

 

[Billy177]

it could did you gap the plugs correctly

 

[Bill Kemp]

Is your air tube back on tight? I left it loose once, forgot to tighten the clamp and it acted like that.

 

[schadler]

What air tube? I replaced plugs and wires...or are you referring to the EGR return tube.

Thanks

 

[Bill Kemp]

Air tube from the air cleaner. I had removed it while changing plugs. Just a thought...

 

[schadler]

Air tube was OK. I took it to STS (we have a great bunch of dudes at ours), and they said it is too intermittent to likely be a problem with spark, electronics, etc. They recommended using Chevron Techron fuel system cleaner first. If that didnt work, they do that $75 fuel system clean.They said most of the other fuel cleaners are crap.

Well see.