Bucking/chugging.... What causes it?

My car seems to be doing this a little more lately.. If I'm at part throttle and let off, then give it part throttle again (babying around town doing 35 in 3rd)... It bucks a little bit or chuggs... -Like a newb driving a stick, but not NEARLY as bad! I'm also pretty much riding on my bump stops, so maybe that's making some of the rear suspension compression worse, causing bouncing? :think:

I know this is common for a RWD vehicle, due to the U joints and the whole setup of the RWD system.

Is this caused by the colder temps and the thicker grease in the U joints? Or is it about time for a U joint replacement? It's the 2k in my sig. It only has 45k miles on it. All synthetic.. RP in the rear, trans, Syth in the PS FL, brakes and Engine oil (of course)


Thanx..

Mine does the exact same thing. I still don't have a tune for my cam though, so that could be contributing to the problem.

I think a lot of it has to do with things loosening up over time and clearances getting bigger. Down the road the axles will not be as tight where they insert into the diff gears, the u-joints will become a little more worn, the tranny gears and bearings as well as the tranny pilot shaft engaging the clutch disk will get a little sloppy. Add all this up you get some bucking, clunking etc.

If all this stuff were new and tight you probobly would not have the problem you are describing. I would check the u-joints anyway.

Also dont rule out cam surge that does not like low RPM's if you have a non stock cam.

Mine does it to.

Air pump?When you let off the gas,the injectors are still pumping gas into the cylinders,so the air pump jacks up the air supply for this ,to level the playing field. I dunno,I'm one my 5Th beer right now.Hope this helps.:cool:

You know in the old days with a cam we knew this was normal

Hmm.. I forgot all about this thread..

It does it, but I really haven't noticed it too much lately.. I'll check it eventually.. I also need a tune BADLY!! Stock cam, but not for long.. I was going to wait till I got my can and maybe heads cause I didn't want to spend $240 twice.. I just need a simple retune...

And I've deleted a LOT of stuff from the car, so I don't have any emissions stuff at all.

Tune can certainly cause chugling/surge. Especially if lean.