I will try to describe this problem as best i can, if anyone has any advice, please chime in.

The Problem: During steady acceleration, not necessarily WOT, the car feels as if im stepping on gas, then letting go, then stepping on gas, then letting go, etc... It also feels that way when i brake as well. Car feels much more shaky at higher speeds, more so at 70 mph as opposed to 50 mph.

Things i've tried:
1. Replaced wheels as well as tires.
2. Got a wheel alignment.

Things that i've considered:

1. Replace the differential fluid
a. Replace the differential itself?
2. Brakes? Could it be brake pads, or possibly rotors?

Anything i can check or possibly test? My last resort would be to bring to mechanic because of cost, but will do so if i can't pinpoint problem myself. Thanks in advanced for help.

 

Last time my friend had these exact symptoms, his front brake calipers were frozen. I suggest you remove the caliper and try to compress the piston back in its bore see if it returns smoothly. Same for the rear.

 

you close to BILLMAN? he's a pretty good mechanic up in NY.

if it was the brakes you should see this, either in the pads, the rotors (major glazing, heat marks, scores), or even when the car is jacked up the wheel would drag.

good luck, hope you find it.

 

^ in my buddy's case, none of that was true, yet when trying to compress the caliper piston, it failed to return. Mr Ak is his screen name here.

 

well then again, he had slotted rotors. They may have caused vibrations with a stuck caliper.

 

This may be hard to decipher, but does the car or the engine seem to be the culprit?

 

I'm not sure, the engine idles fine, revs fine. visual inspection, i can't see anything that looks odd.

 

Okay, so just sitting in neutral, the engine will slowly rev all the way to redline and hold contant rpms? If so, its not the engine, but a driveline issue. Next would be to get the car to speed, then throw it in neutral and coast. Feel anything? Get the car to speed, leave it in gear, and coast. Try those again but use the brakes lightly. See when it happens and when it doesn't.

 

I haven't had a chance to check s2ki all day, i'll have to try on my way to work in the morning. Do i drive to high rpms and then coast while lightly tapping brake?

 

do both - the more different scenarios you can try, the better you may be able to isolate the issue.