Im going to explain the whole story in its entirety, as its all the information I could possibly use to figure out WHAT THE F*CK is wrong with my car. If youre not willing to read the whole story, then dont bother commenting, I respect all of the very knowledgable shops and tuners and hardcore gearheads that roam these Z boards, and I would highly appreciate your input. Please help me out guys

Back in Feb of 06, I was cut off by some f*cking idiot and I admit, I was going a little too fast, and I went over a median. The whole right rear end was damaged. The passenger rear wheel looked like it has 45 degrees of positive camber, and the sway bar was broken off the wheel. Okay, so they tow it back to a shop.

They replaced:
Lateral Arm, Radius Arm, Lower Control Arm, Knuckle, and wheel bearing.

We put on a used 05 19" OEM wheel, and they said the alignment was good and everything .Mind you I payed all of this out of pocket, I did not want to deal with the Insurance company, due to previous issues. Got the car back in 3 weeks, and as I get on the highway, I feel a humming...from 45MPH+ and up, but the car still had its power, nothing else was really affected, but I had this nasty humming, it wasnt a fast humming, more like, HUMM HUMMM HUMMMM, not like a wheel spinning at a fast rate hum... lol

I took it back to the shop to see what it could be, and we put the car on a lift and have someone drive it while in the air. We found very slight movement in the driveshaft, it moved up and down by about 1/4 inch. He said Id be fine for a while but to either re-balance it or replace it with a new one if re-balancing cant be done. Well I put it off for about 4-5 months, but as time went on, it got worse and worse. I took it to a driveshaft shop, and they told me it wasnt fixable and that I had to replace with a new one. Well I didnt have the $650 on a shaft, so I couldnt get this done till now.


Now for the worst part of all this, my car started to get slower and slower and slower over time.The first 2-3 months after the accident, the car was for the most part still quick. But in the next 3-4 months after, the power degraded and degraded so hard over time. It is seriously horrible. When I would mash on 1st when I needed power, there is a HUGE hesitation and the power is just not there. Its almost like the car holds itself back. Its so weird to explain. It feels as if the car gained 1,500 lbs. And now the car is just bad. Idk if the bent driveshaft over time fooled the ECU or something, or if there is something wrong with the differential OR WHAT. There were other symptoms, such as excessive tugging while in 1st or 2nd gear at low speeds, I know manual transmissions have tugging when you dont have throttle applied, but this was crazy excessive.

I think I honestly became a better MT driver, from all this, cuz this whole issue made me figure out how to smooth out on gearshifts, but it was still horrible. I finally replaced the driveshaft, and the shaking and tugging is now gone, but the car is still insanely slow. The humming is still present, but my friends tell me it could possible be my very bald tires thats causing the humming (were gonna swap wheels today to see if we can get the humming out of the equation).

Me and my friends are baffled on what it could possibly be, that is making my engine hesitate so much, it feels so horrible. The motor physically feels that it can just wind out nice and strong, but theres insane amounts of hesitation and no torque or nothing. You have to drive it to feel it for yourself. What I think two things that it could possibly be, is that maybe the bent driveshaft over time messed with my differential, causing this insane cut of power, or that my ECU adapted to the driveshaft and somehow hardcoded itself with its slower rotating speeds or somesh*t? I have tried an ECU reset (pedal method, but I will do the overnight disconnect to make sure), I have tried Fuel System cleaner (for sh*ts and giggles), Ive tried the MAF cleaner, and nothing. Could my injectors possibly be bad? The last things I am going to try, is to put my stock intake back on, and swap wheels with my friends Z (to see if we can get rid of the humming). If I cant find out what is wrong with my car by the end of this weekend, Im making and appointment with the dealer on Monday. I havent taken it to the dealership because they have no knowledge of the accident, neither does my insurance company, so I tried to cover this up by myself and I cannot figure out what the hell is wrong with the car. But Ive had it, and its going to the dealership on Monday. Please fellas, any input would be highly appreciated.

 

I would edit or reword this post so certain things you said cannot be used against you later if push comes to shove. You never know who is reading this post.

 

That's okay, maybe some Nissan dealer guys have some input of their own

 

When you say the shaft moves up and down, do you mean it moves in the vertical axis or along the car's length? I doub't the shaft can be bent. Carbon usually shatters instead of bending.

When you had the car fixed, did they check the chassis' integrity? The car might be the one that got bent, not the shaft.

Do a wheel swap to isolate the humming. If it's still there, it's probably the diff.

How's the fuel mileage? If you had mechanical drag, you would get poor mpg.

The power issue might be a different problem. Bad throttle assembly, bad gas (where do you fill her up?) or simply dead spark plugs. These should last longer but many guys have had to change theirs.

 

When the shaft was moving, it was moving up and down vertically, looking at it from under, it was a very slight up and down movement. I dont understand how the shaft couldve been whacked in the accident, its so far up inside the frame of the car. It wouldve broken the exhaust if anything. The first thing we saw was the movement in the driveshaft, so we immediately pointed it suspect for the humming. But after the accident, the car was still pretty fast. I have replaced the driveshaft, but the humming is still there, just the shaking and tugging symptoms arent there. The power degradation has to be an ECU issue, im pretty positive, but the humming I still dont know. Thats why Im going to change wheels with my boy to see if that could possibly be it. Mileage has worsened, but not drastically like the power. The power issue actually helps me to stay at low revs, because the car simply doesnt go. It feels very choked. Do you think possibly swapping a MAF could work?

 

I don't know if this will help anything at all... but... disconnect the battery for 20 minutes to an hour and connect it back. Drive and see if hesitation is still there. If the hesitation is still there it could rule out electronic problems? Maybe? Then it could be traced to a physical problem. Check tranny and differential fluid just in case or get it changed. Basically do every preventative maintenance item on the rear setup.

 

the hubs will cause a vibrating or humming noise, and the diff may have something to do with your lack of acceleration.

 

The wheel bearings could possibly the noise and I would try your friends MAF.

 

My friends and I

 

Reset your ECU. Change your diff. fluid. Your diff could be damaged do to all the added vibrations but change the fluid first since it is easy and cheap. When you get the car in the air on a lift spin the wheels and see if there is any movement.

 

I have further updates

One of my boys that works at the Infiniti dealership did the favor of running some tests on the car. He connected this computer to the inside of my car ( I believe its called Nissan Code II or something like that) and checked my ECU and injector firing and ECM and BCM modules. He said everything looked normal. I explained the entire situation to him and he thinks it may most likely be the Diff. My car also happens to burn oil (wonderful world of Rev-Up Motors), but he said that wouldnt cause the hesitation and degrading of power. Im going to swap wheels sometime this week with my friend to rule out the humming, hopefully that goes away. My friend at the dealership advised me to put the stock box back on and bring it in for inspection by an upper level tech. I need to get this entirely fixed

 

I'm gonna tell you what the problem is.....read my highlights.

thunkity thunk you shoulda addressed that issue....jmo.

(BTW, I'm interested in a tuner who can make his way as a "drive shaft shop" I wouldn't guess there's much of a need for replacement "drive shafts" except down south.....maybe a "drive shaft slash clutch shop"...just guessing.

 

we all know who is reading this and that was heart felt.

 

opps, might have been wrong just a guess. And more importantly, you became lazy because you thought the guy was really an @$$#0!=, (when he wasn't.)

Pennsyltucky...is up there with Fontucky

 

WTF are you exactly talking about?

 

Its easy enought to get your shaft chked for balance -----DO SO----Hate to see a CF Shaft blow (terrible mess) There is no reason a GOOD shop ( I have one) cant make you an aluminum shaft if need be----I have a good amount of custom shafts made for me for different things and (my shop) seldomly over a couple hundred bucks

 

I want some of that stuff he's smoking, I know the Pennsyltuckey part was from my profile but the other stuff I have no clue.

 

have you tried getting your O2 senesors checked??