Shake Under Acceleration

[MitchFromPEI]

I have a 2003 ZR2 GMC sonoma. 4.3L Lately it started to shake a little under acceleration. Around 50-70 Km/H. If I let off the gas it goes away. So I started to think maybe the timing is a bit off? That would cause a shake? Seems to fine at highway speeds (100KM/H +) Motor mounts is something to check too. Any other ideas?

[jro909]

probably mounts...if it was timeing i'd assume itd run like poop all the time

[Nytemare]

U-joints around those speeds man.

 

Have them checked out, but I would say with 90% certainty..they're toast

[MitchFromPEI]

U-joints around those speeds man.

 

Have them checked out, but I would say with 90% certainty..they're toast

 

You mean the universal joint in the drive shaft? I'll have them checked. Thanks

[MitchFromPEI]

Might I add I only feel it really from the front end/steering whee, under load. I also have a harder time starting lately, takes a little bit more turning over and then a rough start. Is why I was thinking timing, as it does have a little less power than usual.

[Nytemare]

Might I add I only feel it really from the front end/steering whee, under load. I also have a harder time starting lately, takes a little bit more turning over and then a rough start. Is why I was thinking timing, as it does have a little less power than usual.

ok...Still have the U-joints checked...just in case.

 

I would do a tune up.

Your timing is ECM controlled in your truck...so it is not off...unless your timing chain has gone tits up...which is highly unlikely. And if you jumped the timing chain, the CEL (Check Engine Light) would be on.

 

You cant change your timing by twisting your distributor on your truck.

[MitchFromPEI]

Might I add I only feel it really from the front end/steering whee, under load. I also have a harder time starting lately, takes a little bit more turning over and then a rough start. Is why I was thinking timing, as it does have a little less power than usual.

ok...Still have the U-joints checked...just in case.

 

I would do a tune up.

Your timing is ECM controlled in your truck...so it is not off...unless your timing chain has gone tits up...which is highly unlikely. And if you jumped the timing chain, the CEL (Check Engine Light) would be on.

 

You cant change your timing by twisting your distributor on your truck.

 

 

OK, i'll check mounts and U-joints. I know how to check mounts. What about U-joints? Last time I replaced one it was making a noise under accelleration. I just did ball joints too, so it's possible something isn't lined up correctly.

[Nytemare]

Might I add I only feel it really from the front end/steering whee, under load. I also have a harder time starting lately, takes a little bit more turning over and then a rough start. Is why I was thinking timing, as it does have a little less power than usual.

ok...Still have the U-joints checked...just in case.

 

I would do a tune up.

Your timing is ECM controlled in your truck...so it is not off...unless your timing chain has gone tits up...which is highly unlikely. And if you jumped the timing chain, the CEL (Check Engine Light) would be on.

 

You cant change your timing by twisting your distributor on your truck.

 

 

OK, i'll check mounts and U-joints. I know how to check mounts. What about U-joints? Last time I replaced one it was making a noise under accelleration. I just did ball joints too, so it's possible something isn't lined up correctly.

 

Ahhh if you didn't get a front end alignment done yeah...its likely way out.

 

I usually just replace them if I have any vibration issues around 70km/h...they're like 30 bucks...

But what you have to do is check them for sloppy movements by hand. Just watch them as you move the driveshaft...

[PwrdByWinchester]

Easiest way to tell if it's in your suspension or not is to do this. Start the engine, with your left foot holding the brakes, put it into drive and give it light throttle. This will simulate putting the engine under a load. If you feel the 'shake' (miss) then you'll know it's an engine problem.....not drivetrain or suspension.

 

When was the last time the engine was tuned up? Are you mechanically inclined enough to pull a spark plug and check its condition? If you decide that it in fact DOES need a tune up, I'd have the complete fuel system professionally cleaned.....then have the spark plugs and wires changed.