'98 needs help

[Landchipper]

I need some assistance. My Tahoe is the 5.7 engine auto/OD tranny. At highway speeds with the rpms at approx. 1800 to 1900 the engine seems to have a severe miss and the truck "bucks" and lunges. No codes show up on the computer diagnostic. I have replaced the O2 sensor, the coil, the dist. cap and button as well as tried all octanes of fuel. The trouble seems to occur when I begin to go up a slight incline in the highway when the engine needs to advance timing and unlock the torque converter to gain more power. I will give any other information that is needed for your help.

Any ideas will be utilized with great appreciation.

 

[SunlitComet]

how about ignition wires or plug damage? does your scanner read cylinder misfire history or can you get to one that can? i would look at that first to help narrow the cause.

 

[Landchipper]

I will get to that this weekend and report back.