My 2003 Suburban 1500 with 170,000 miles has started having a small jerking when in overdrive. Usually around 2K RPM cruising along about 60ish. It starts jerking, not hard but you can feel it while driving. It isn't throwing any codes or anything, and it stops if I punch it and raise the RPMs. A few have told me to change the coil packs, but I don't know how to test them, and I really can't afford to spend the 250 to change something I really don't need. Thanks in advance

 

Do the rpm's change with the jerking? Do you feel like it's a motor miss or a drivetrain problem. Does it do the same thing shifted out of overdrive at the same rpm's?

 

Sorry, I meant to include that, but no, I can't see the rpms change when its jerking. And yes, it always seems to have the shake or jerk at low rpms, regardless of the gear. I just notice it more in overdrive. It feels to be more of a motor miss than anything,but I'm no expert by far

 

So you would feel the same thing if shifted in 1st gear at low speed at the same rpm's? Any change in 4x4 vs 2 wheel?

 

Let me check that 1st gear thing here in a few minutes..lol...its not a 4 wheel drive btw

 

1St gear it seems to be fine

 

Do you notice it more if going up a grade when the motor's under more load? How about going down a grade, foot much less on the pedal? (sorry gunna empty your tank with all these questions) - I'm trying to get a feel for motor vs drivetrain source of your problem. I won't come up with a fix but there are others here that I bet will in the next couple of days.

 

Ask all the questions you can think of. I need to get this fixed asap before vacation next week. Yes, it definitely does it when the motor is under a load, not so much when just cruising along

 

So I vote for a motor source. When was last time a good tune up & filters change performed?

 

Good question. I bought it used with about 140,000 miles on it. It was a 1 owner vehicle but I have no clue when it was tuned up.