Since I purchased this truck with 52K miles on it I have been having this same problem repeatedly. The dealership where I purchsed it "tried" to fix it with the diagonoses of misfire on cylinder 5 several times with no luck and recently I took it to a GM dealership and they said it would just be a shot in the dark until we find the part causing it. Since the diagnotic machine does not give a definitive reason this is happening. I don't have 1000's of dollars to keep replacing parts until we hit the right one so I was hoping you may have some better insight than what I have been getting.
Here is what is happening. When I accelerate it does just fine when I reach between 1300 to 1500 RMP and 55-60 MPH the engine shakes like the motor mounts are broken. If you press the gas and change the RPMs or move past 60 MPH via passing gear not steady RPM gain it goes away gradually. This happens on the slightest of hills now if I am climbing a larger hill or towing. Basically any kind of load on the motor it is horrible. I have changed plugs, wires, fuel filter, DC and RB. I hope someone has some good information on what I can do to fix this. I want to keep the truck so come on guys help me out!
have the same problem?
Sunday, October 28th, 2007 AT 8:30 PM