More dreaded vibration!

[Amigo75]

Hi, apologies in advance for babbling on but i am new so i'm bound to go OTT, i would appreciate any help/advice that anyone may have. I registered yesterday after reading threads that seem to be related very similarly to the issue that i currently have (namely the thread called 'the dreaded vibration'). I own a 2003 Golf Mk4 GT TDI PD 150, i think it is a great car and it has always been a pleasure to drive - well until i had an argument with a 'munkjack deer' back in Oct 07. I'm not sure if the accident is related to my troubles or not, the repair was undertaken by an 'insurance approved' garage (NOT VW) but after a few niggles with the finish of the paint job and bumper alignment, the repair seems to be a good one. The problem started as soon as i received the car back from the repairers so i naturally assumed the problem was repair related - i jumped up and down, threw my toys out of the pram and eventually got the insurance company to allow the car to be assessed at my local VW garage. The problem was what i can only explain as a 'chugging' noice coming from the engine bay upon cold start only (it doesn't do it at all when warm, including re-starting). I also experience a vibration through the foot pedal/floor pan whilst accelerating and under braking between approx. 1300 & 2500RPM (this is constant and in all driving conditions)!

Although VW couldn't explain or diagnose the cause for the vibration under braking, i was advised that the cause for both the cold starting noise and the vibration whilst driving was due to the DMF (it was explained to me that normally a faulty DMF vibrates only under acceleration - not braking). Estimated at £1127 for replacement i questioned if there could be any other possibilities as i didn't want to spend out on something that did not need replacing - i was reassured that the DMF was the cause and progressed with the repair.

It turned out that the DMF was not the cause for either issue. I had my wheel balancing checked and corrected, which did improve the vibration a little (and solved the vibration under braking) but both issues are still there. I am out of pocket, but more frustatingly, upset that my Golf is still unwell - i am in need of some good advice from owners that may understand these issues or have experienced this themselves.

I had the car serviced last week and hoped that one of the serviceable parts changed would be the solution - IF ONLY! The car had covered an astonishing 28k miles since the last service and aparantly the air filter wasn't even changed (not part of the intermediate long life service), could it be starvation of air due to a blocked filter?.... VW did check for any fault codes but results came back clear (although from what i have read, this may not mean that things are ok), the guy in VW suspected the MAF but after driving it said that it drove perfectly - i am not convinced and can only assume that the roads that he drove it on were uneven and disguised the vibration.

Someone did recommend to another member of this forum, testing the car whilst stationary (to illiminate suspension, engine mounts etc), i tried this and the vibration was present (it almost feels like the engine is misfiring/running lumpy throughout this part of the rev range)...If anyone has got any ideas, i'd be grateful of your suggestions? Thanks

[Nutty]

Someone did recommend to another member of this forum, testing the car whilst stationary (to illiminate suspension, engine mounts etc), i tried this and the vibration was present (it almost feels like the engine is misfiring/running lumpy throughout this part of the rev range)...If anyone has got any ideas, i'd be grateful of your suggestions? Thanks

Well you have identified where the problem is at least, it could be to many things to go through on here, you need a diagnosics plug in on a rolling road to see where the problem is occuring, you could try the hit and miss approach of course, injectors, fuel lines, filters, when was the timing belt changed ? not recently ??

Did you check out the thread by RS Tuning, offering a rolling road test/report

[Amigo75]

Thanks for the pointers. I had my MOT on Saturday and the tester (who i've used for years and trust) mentioned that my O/S front tyre was low, but not down to the min markers - but because i had a puncture on the N/S front tyre in Dec 07 (which needed replacing), the difference in tread depth between the 2 tyres could be making a contribution. I had it changed straightaway and there WAS an improvment. In addition, although i had my annual service at VW about 2 weeks ago, the air filter was not changed (as it is changed every other service according to the schedule). For the small amount that the parts cost, i replaced the air and fuel filters yesterday and man, what a difference... 'shes back to her good old self again' PERFECT! Cheers for the advise - i may think of having a road test anyway just to see the outcome