2004 GMC Sonoma - Engine Skip

If the Sonora is a full time 4WD (i'm not sure that it is) the "skip" can be caused by uneven tyre wear or pressure from front to back. Thus you get one axle actually going fasret than the other. The transmission and tyres take up the difference until they cannot take any more then a tyre/s slip a little bit giving a "skip" sensation.

Hope this helps

Does the problem only exist under load or will it do it at any point in time? I had two vehicles that developed coil problems that produced engine skips. The engine that had the coil-on-plug set up didn't toss a code and was more prone to skipping under load, but would do so occasionally just going down the road. The other coil problem was from a single coil, electronic igintion system and the OBD 1 diagnostics didn't toss a code either. This one was actually more than a skip, it felt like the car quit for a quarter of a second and then came back on and ran normally.

I have heard, but not experienced, that the same type of skipping can be caused by a spark plug and at 72,000 miles that is also a possibility. Again, no code.

These problems were solved as much by luck as experience, with a lot of time spent thinking seriously about the limitations of the on board diagnotstics systems.

Good luck in sorting this out, but my money is on an intermittant electrical issue.

Writer,

The skip normally occurs on acceleration. Since the dealer flushed the transmission the problem is occurring more. This make me think it is either the transmission or torque converter. I already paid the dealer $400 to flush the transmission and some other minor work. I'm going to let them look at it again. The big issue is I have an extended warranty on the truck that runs out on Feb 9.

Thanks

PLCMan

If it is an re-occurring problem, ask the dealer to keep the repair order open till the issue has been resolved. Does your warranty cover a rental car? If so, then don't return the car till you test drive yours and the issue has gone away. Tell them also that you don't have the funds for someone to gain experience on your vehicle. They also have service contacts with GMC to help diagnose problems.

Ford has an on board recorder. This can be connected to the vehicle and placed by the driver. There is a hand held unit that has a button on it. The operator can push this button at any time while driving the vehicle. It will record the operation of the vehicle at that moment in time that it is skipping. This can help the mechanic diagnose the problem.

I had one problem that was quite the same Is the transfer case, I though mine was like my old chevy truck only to find out these transfer case have clutches, They have a week oil pump that gives out and sometimes wheres through the case itself as was mine, though i could not see the hole, it leake out when driving, these transfer case require a special gm blue tranny fluid and dextrom will only shortern the life of these transfer cases. when the oil pump goes out the clutches in the transfer case will fail and lock up in 4 wheel drive causing the skip.

Does it have fully electronic ignition or are points still in use?

Andy

Electronic ignition

Try holding your foot on the brake and gunning the engine and determine if it missing or in the transmission. Until you know what is going on your just wasting money.

rhandwor is absolutely right. Hook that thing up to a good ignition 'scope and see if the secondary/primary signals are breaking down by running up the rpms while holding the brakes locked.

It sounds like you're getting some poor service so far. Dealers are not really that much better. It's a mystique they want you to believe..

Thanks for everyone input. I may have corrected the problem. Last week all of a sudden the truck starting running ok. The only thing I did was fill the gas tank. After the fuel got down to 3/4 full the problem came back making it look like it could be low fuel pressure. The dealer told me it was a little low but was OK. I changed the gas filter a 2-3 months ago but changed it again and it appears the problem went away. I guess there is a possibility that I got some bad gas and the filter was clogged.