I am the proud second owner of a 1997 GMC Yukon & have been since 1998. She now has over 200,000 miles. About 1 year (& 10,000 miles) ago I had all the spark plugs replaced. About 1 month ago she got a new fuel pump (in the gas tank) and a new fuel filter.
Here is the ‘problem’: for the past several years & still today at about 2200 RPM on the Interstate at about 70~ish MPH consistently only under those conditions the Yukon “misses-out” a bit. It never quits running and is mostly ackward & annoying when I am driving my carpool buddy.
Waddya think?
No, I don’t think it’s caused by the presence of your carpool buddy. I DO think that it’s probably an ignition issue. Change the spark plug wires. Test. Disconnect each spark plug wire and observe it’s spark across a gapped spark tester (available from the auto parts store). If the spark is weaker from anyone(s), suspect the ignition coil(s).