I drive a 2003 F-350 with the 6.0 at work. During the winter months, the trucks idle extensively due to the cold and remote locations don't have electricity to plug in. Last winter the truck lacked power and would hardly drive 45 MPH down the road. I brought it in for service and they found that the cat was plugged. They had to remove it and physically dislodge the build-up.

I always idle the truck at higher RPM's (with AIC) to prevent this and keep the engine temp up. 3 other co-workers also drive the truck and a couple don't engauge the high idle. Last week the truck was exhibiting the low power again and the check engine light was on. I suspected a plugged cat. I engauged the high idle at about 1700 RPM for a few hours to heat the cat. I them drove it down the road. In Drive (auto tranny) the truck would max out at 17 MPH and not exceed 2100 RPM. It didn't feel like it was shift out of about 2nd gear. If I manually put it in 3rd I could barely make 35 MPH at about 3000 RPM. I drove it back and forth a 1/2 mile section of road to blow out the build-up. After about 2 trips up and down the road, performance was back to normal, but the check engine light was still on. Re-started the truck and CEL was still on. Idled the truck at 1500 RPMS while parked. CEL went off about 1/2 a day later. Every thing seems back to normal again.

I want to nicely inform my co-workers of the importance of utilizing the high idle. I would also like to inform them of why the cat is plugging off. Is it because of unburnt fuel accumulating in the cat when the cat is not warm enough to burn off the unburnt fuel? Or is it blowby oil accumulation in a cold cat? I doubt it is engine oil because the oil level remains constant.

My supervisor is looking into a Cat delete pipe. These are private roads, so I think we are exempt from federal highway requirements. They may be concerned about warranty issues with the local dealer involving a Cat delete though.

 

hair *****!

 

In the good'ol days, with a plugged 'or' rattling cat, we would 'rod' the cat out.. Completely gut the inside, and keep the outside look'n legal.. A delete pipe can be trouble here..

....................HP..................

 

I think the only way to resolve this...run four dyno pulls with it in and four with it out.....I still say leave it in, however I know some will not go with an answer until it is on the dyno sheet.

 

I would almost for sure take it off in the winter and maybe replace

it in the spring or summer. My 2cents.