i have a 2001 chevy 2500hd 4X4 crew cab(138,000mi/4300hrs)with the 6.0L engine. I have a intermitant missfire that sets a soft code(multiple missfire), my tow haul wont come on, and my fuel gauge jumps all over the place.

(missfire) I have heard of the ecm ground wire on the right head but havent been able to locate it yet. I put plugs in when i bought the truck they have 22,000 mile or so on them. I just replace 2 coils cause they were sparking from the coil to the metal holder on the outside of the coil. Also new wires like last week. Fuel pressure is at 45-50 psi idling. When it runs bad it has no power very rough idle. Makes the SES light blink. No smoke from over fuel. Then it just clears up like you fliped a switch. May not do it again for few days or hours. But is mostly in morning when you first start up. It is also hard to start in the mornings after siting all night. It has to realy whip over for it to crank.

(tow haul) dont know much about this one just the fact that when i push the button the light doesnt come on. And no change in trans function.

(fuel gauge) the fuel gauge just jumps from full to empty. mostly when full of gas about 1/2 tank it reads pretty good .

Also have a bang in the drive tran when taking off from a stop. it happens just alittle after take off . You get this tump like sometings loose buti have been all over the drive line and cant find any thing loose. Right after i bought this truck once and awhile it would sift real hard from 1st to 2nd. but since has stopped this.

Hope someome cam help me.
thanks for you time.

 

Check your plugs. If your engine code told you what cylinders were misfiring then try changing the plugs and wires to another. If the same cylinder misfires it the coil or not getting fuel. If another one does it't the plug or the wire. You may want to see if you can get your coils checked too. Your tow haul may be a fuse. It sounds like you aren't getting power thur the circut. Check your fuses. If not you will need a book it may be a bad sensor or the button itself. The fuel guage sounds like a bad sending unit or a bad ground. Probably a sending unit. All the gauges should ground together. If it is a bang more than a thump I would guess tranny. That will more than likely need rebuilt. If it is more of a thump it may just be u-joints. If you can move the drive shaft side to side and get u-joint to slide in the caps they are more than likely bad.
Good luck

 

My 2000 6.0l is doing the same thing misfire and Klunk sound I assumed the Klunk was my t case since I know it's bad but the misfire has me stumbled I have replace 1 02 sensor and just picked up the other 3 since I had 7 codes for 02 sensors, I'm not sure if this will help my misfire but can't hurt! I also noticed mine does it worse when it's wet out. Did any of this info ^ fix yours? Any other ideas would be appreciated thanks!