I have a 2002 4X4, 5.9 6 speed. I recently was running a blend of WMO & D2 but due to the smoke and loss of power I figured I would run it all out and fill up with fresh D2, this solved the smoke issue but now when I get in 6th gear and hammer on it the truck will perform fine untill it hits 65-70 MPH, and then the gear shifter starts hsaking back and forth like crazy. I have just changed the fuel filter and that had little or no effect. Any ideas?

 

I just scanned my codes and it says "P ECU" and then "P DONE"......I am guessing no bad codes are showing

 

Sounds like you have a tip partially plugged in one of your Injectors. I would first hit it with a really heavy dose of Power Service and run it through, see if it comes out of it.

 

I have a fresh can of power service that treats up to 250 gallons, how much would be a good healthy dose? Thanks for the advice by the way! I have also noticed a greyish smoke when traveling at high speeds and more black smoke than normal during take off. A loss of power is slightly noticeable too, but mainly at the higher speeds....

 

Would one injector being partially clogged make the truck vibrate like that? and have a loss of power at higher speeds along with greyish smoke?

 

Yep, and I would probably hit it with about a third to a half of the bottle.

 

Ok, I went ahead and put about 1/2 the bottle of PS in with a full tank of D2. The truck still seemed sluggish and was putting out a lot of smoke so I took it to a mechanic for his input. He said he thought the cat was clogged up from me running the WMO and that removing it would solve the problem and make the truck drive better. I went ahead and cut the "cat" out and it was nothing but a large muffler looking piece with a solid pipe through it. It almost appeared to be a fake cat used for inspection or something. none the less, I did notice about 1/8 an inch of soot build up inside the exhaust. Did the 2002 not have a cat? and more importantly this did not solve the problem, I am taking it to a muffler shop in the morning and going to go ahead and have a 4 inch turbo back exhaust installed anyway, but I doubt this will solve the problem it was just something I wanted to have done eventually anyway. At Idle the truck still has a slight white smoke, maybe I am not being patient enough for the PS to take effect but any input would be great. I am obviously new to all of this and lacking in knowledge....

 

The '02 trucks don't have a catalytic converter (unless it's a CA truck). They were equipped with a resonator and muffler.

If you just put in the PS tonight, run that tank through and see how it behaves. If you really load up on the PS, you should notice a quieter engine when that PS is circulated through the system.

 

Gettin that kind of shake at the higher speeds seems to me its a driveline balancing issue, possibly.

A clogged injector is clogged throughout the rpm range, not just at cruising speed.

Just my .02.