Misfire issues

[Jason98]

My 06 1500 ram 4.7 V8 250,000 miles. has been giving me misfire and bank 1 sensor 1 issues. Catalytic converter was replaced along with spark plugs. Less than 15000 miles was having misfire codes again. Spark plugs were fouled. Replaced plugs and also changed the ignition coils. Had codes again and now the Catalytic is plugged. Wondering what I should do. Do I replace the cats or do I bypass them and if so how?

 

[3pedals]

How do u know catalytic is plugged? The cat on my ‘08 4.7 never got plugged but started throwing an efficiency code around 300k miles, though it still ran fine. Some tweaker stole my useless cats earlier this year at about 350k so insurance put new ones on ($$$ bc CARB approval) and no longer have to do the o2 spacer trick to pass smog.

My point is, you shouldn’t be plugging cats so quickly if at all. Something is allowing too much unburnt fuel thru the engine if your catalytic is plugging. O2 sensor(s) been replaced? Maybe leaky injectors?

With 375k miles on the truck now, I’ve still never had to change injectors and have only had to change O2 sensors once (well twice, if you could the ones the tweaker cut off with the cats).

Sounds like maybe an air/fuel meter might help diagnose your problem

 

[Fast69Mopar]

My 06 1500 ram 4.7 V8 250,000 miles. has been giving me misfire and bank 1 sensor 1 issues. Catalytic converter was replaced along with spark plugs. Less than 15000 miles was having misfire codes again. Spark plugs were fouled. Replaced plugs and also changed the ignition coils. Had codes again and now the Catalytic is plugged. Wondering what I should do. Do I replace the cats or do I bypass them and if so how?

There are two main things that hurt catalytic converters. Excess fuel and oil.

How did you determine that the cat is restricted?

What do the downstream (after cat) oxygen sensors look like? Are they fouled with fuel or oil? Is the tip completely covered with soot where you can't see the holes?

Does this engine have alot of blow-by?

 

[Jason98]

Took it to the dealership to have it looked at. They said its plugged. I took out the upstream O2 sensor a n d it was black and had obvious excessive heat coloration. No blowby. Holes covered by soit.

 

[Fast69Mopar]

Took it to the dealership to have it looked at. They said its plugged. I took out the upstream O2 sensor a n d it was black and had obvious excessive heat coloration. No blowby. Holes covered by soit.

What do the downstream oxygen sensors look like? Same thing? Covered in heavy soot?

A quick look at the Short Term & Long Term Fuel Trims would tell us a lot about what is going on with the engine.

Does the motor use oil between oil changes? Are you having to add a quart or two?

 

[Jason98]

I have not had a chance to look at the downstream sensors yet. Fuel trim?
Doesn't use oil. Changed every 3000