Hey guys,

I'm having somewhat of a major jerking issue that I want to get taken care of ASAP. I rather do the work myself if I can and save a few bucks.... But I have no idea whats going on, which is why I'm hoping to get your input.

Recently I had a few leaks in the engine and replaced some parts. I don't think its related to the issue, but i'm just giving the recent background. I had the car inspected by a shop and gave me a full quote and breakdown of what I needed. I ended up doing all the work myself and everything ran fine for about 2 weeks. Then all of a sudden during a moderate to hard acceleration from a stop sign or light, the car would do a hard jerk as if I suddenly hit the brakes. Obviously being worried, I would ease off the gas and then slowly accelerate and it would be fine. Its not the usual acceleration flutter that everyone asks about. This is a hard jerk as if I was rear ended or if the engine shut off for second. Sometimes during hwy speeds (60ish mph) I can feel this jerk coming along so ill let go of the gas, it'll go away, then ease back into the throttle and everything is fine. Hoping it was just a clogged fuel filter, I replaced it again (only 3k old), but still has the same issue.

No CELS are thrown. Checked OBD for any stored codes, nothing. The car is at 108k miles, b7 a4 2.0t fwd auto. Just to give more info, the recent parts I replaced are:brake light switch, fuel filter x2, low pressure fuel pump and control module, brake vacuum pump, coolant temp. sensor,
oil cooler gasket, oil filter housing gasket, coolant flange(rear of engine), thermostat, a few hoses, and the obvious oil w/filter and coolant.

Any input would be greatly appreciated.

 

Have you changed your cam follower yet?
You may have low fuel pressure from a worn follower or HPFP

 

I did actually. I think I replaced it right around 80K?

When I did the recent work I had to remove the HPFP to get more room. I inspected it again since I was already there and everything looked fine.

 

Something like that happened to my 2006. It would jerk when accelerating. It turned out to be a bad coil. It went on for 3 months before it finally threw a code. I thought it might be a coil early on, but the service department couldn't duplicate it or get it to throw a code.

 

It does sound like when I had a coil pack going. Eventually, with enough WOT runs I got it to throw a misfire code, had the shop look at it, they figured out which and replaced the bad coil and it was fine.

 

Being that you have an auto FWD trans (CVT) it could be transmission related. They are notorious for having issues. Could be as simple as it needs a fluid change/top off.

I'd have it looked at by a professional.

Jason

 

What year B7? There's a big difference in the cvt from 2006 to later. 300 for just the fluid change and adaptation. 500 or close to it for the inline filter to changed as well. The filter is external and the internal is more of a screen. Dealership prices. You can do this at home with vagcom if you have it. Vagcom version yo u need is 400.

If you don't have vagcom get it to the dealership or find a euro that does.