01 chevy silverado 5.3 misfiring ?

[Northland Sportsman]

On my way home from LOW pulling a trailer w/ 2 whlrs my truck started having major problems. We stopped for a break and and it seemed fine before hand, then it wouldn't get up to speed, running very rough, no power. only able to get up to about 45 mph. Dropped the trailer in Grand Rapids and limped home at about 40-50 running very rough. Dumped in some heet but no help there.

Put it on the machine at my buddy's shop and it is misfiring on cylinders 1,5,7. gas in the oil. pulled the valve cover and no broken springs and all moving as they should. Kind of stumped on this... Any help or suggestions appreciated. Thanks!

[Jeremy airjer W]

Plugged Bank 1 Catalytic converter.

[Northland Sportsman]

thanks, can you tell me how to check that? Also forgot to mention, and probably not related but who know, discovered that what looks like and ideller pulley on front towards passenger side of vehicle is bad, outside edge all broken up.

Would the plugged converter set off more codes? only one is misfire on those cylinders.

was also told it could be o2 senser?

Thanks again, I need all the help I can get!

[Jeremy airjer W]

You can pull the upstream O2 sensor on that side and check for back pressure.

If it where the O2 sensor it would be stuck extreme rich or extreme lean and should have flagged a code. If it didn't it would be obvious that it was looking at scan tool data. If it is stuck at one extreme or another than you should be able to unplug it and get the engine to idle smooth and run a lot better. Also short term fuel trims should come back into the norm if there are also way out of range.

There are two cats, one for each bank. There is no code for a plugged cat, there are only clues which your engine is giving you.

[Northland Sportsman]

Thanks, I will check that and/or replace that side to see if that does the trick.

[Northland Sportsman]

good call on the plugged cat converter! Thanks for the help, back up & running again!

[Jeremy airjer W]

Thanks for letting us know the fix!