So, saturday afternoon a friend and I decided to disect my exhaust.

I was wondering how "free flowing" the cat would be after 165,000 miles.

Well, about half of the holes were plugged with soot, and the other half were severely restricted.

I wanted to hear about how loud the truck would be with a striaght pipe... also wanted to know what the turbo would would sound like.

This is where it got kind of interesting...

Quickly applying throttle from idle the engine the engine missed... badly.

It sounded almost as though it was running on 4 cylinders.

Also, when the exhaust went back on, sans catalytic, there was no notable miss under the same conditions.

My question is has anyone else experienced this phenomenon in this situation?

Everything at this point leads me to believe my PMD/FSD has gone south.

I found a source where I can a new one for $216.00

I guess the next logical thing is to replace it.

I am trying to hold off until I get my cast aluminum heat sync done.

If anyone has experienced this same problem, or can offer some explaination as to why this would happen, please share it.

Bob250,


Turbo driven high compression systems have to evacuate a large volume of hot gas. The system will always work better with fewer restrictions. Edited by: quantum mechanic