Shuddering While Cruising On Load

July 30, 2012

Hi guys

Hoping someone can help me here.

A couple of weeks ago my car (57reg 2008 Avensis 2.2 D-4D T180) started shuddering a bit while cruising on the motorway when I hit an incline. Seemed to be ok on a flat or downhill but when I hit a slight incline it would shudder a bit. Dropping a gear and accellerating would usually stop the shudder. Symptoms got worse until you couldn't cruise above about 60mph without it shuddering violently, even on a flat!

Various people speculated about it being driveshaft(s), flywheel, tyre balance etc. Had tyres re-balanced (VERY sceptical as to whether it could possibly be tyres as it felt nothing like a tyre balance issue and the symptoms seemed to be caused by throttle/engine load rather than vehicle speed) and driveshafts inspected and nothing obviously wrong without stripping down. Symptoms still persisted. One person suggested it being a misfire (because the shudder seemed to stop when letting off the throttle) and that I should use a good fuel system cleaner. Having bought a case of BG244 some months ago (as I like to use a can of this and a can of EGR/air intake system cleaner after every 10k mile service, although I must admit I forgot to use a can on the last service and never got round to fishing one out of the shed, and now it's just had its next service so has gone 20k miles without a can of BG244). I used a can of BG244. After using a quarter of a tank of fuel the symptoms did seem to get less intense and by the time I'd used three quarters of a tank the symptoms seemed to have gone completely. On my next fill up I added another can for good measure (as I forgot to add it on the last service and now it's just had its next service), my theory was that if the BG244 had only just had enough of an effect to make the symptoms go away, the injectors or whatever might still be a bit clogged but have been cleaned just enough not to make it shudder and so might still be clogged and therefore not being long before symptoms came back. Having got through about half a tank of fuel on my 2nd dose of BG244 the symptoms seem to be coming back slightly. ODD! Anyone got any ideas what could be causing this, if not a misfire due to clogged fuel system???

Kind regards

Mike

July 31, 2012

hi matey

check with:

- EGR (carbon deposits)

- fuel filter (dirty or not)

- fuel filter --- have an air bleed from filter thru an air escape screw.

regards / Igor

August 6, 2012

EGR Valve and the opening to the inlet manifold was cleaned 20k miles ago. Was going to do it again within the next few days, hopefuly this might help, but I doubt 20k miles worth of carbon would have this effect as some people do over 100k miles without so much as even looking at the EGR valve without having any problems, I believe???

Fuel filter had only done 20k miles since it was replaced last and the service schedule says they should be good for 40k miles before needing replacement. Changed it anyway, it did look a bit black inside - made no difference though!.

Anyone know if this could possibly be a flywheel or driveshaft issue??? My initial instinct would be to think no, because when it starts shuddering it seems to lose power (just about manages to maintain the speed it's doing but unwilling to accelerate at any great pace while shuddering, otherwise while it's not shuddering acceleration is fine). Surely if it was a flywheel / driveshaft issue it wouldn't cause the slight power loss symptoms like this and it would just accelerate out of the shudder???

August 6, 2012

Also, it seems absolutely fine at lower speeds. Anything below 50mph and the shuddering doesn't happen at all. You can rev it while stationary and the engine sounds perfectly smooth to me (although I'm not an expert!!!). Accelerates beautifuly at low speeds (0-50mph). In fact, most of the time it accelerates fine from 50mph and upwards. Just seems to be when cruising at between 50mph and 75mph while going uphill that gives it the most problems, especially when the car is loaded it happens more often.

August 17, 2012

Ok, it's been going away and coming back. Had a few days blissful cruising, even uphill with 4 passengers and luggage and had no problems at all cruising all the way from 50mph to 80mph. However, it's come back again! Something that's been suggested to me is that the clutch and/or flywheel is breaking up, a small chunk will break away causing it to spin off balance, but when you wear it in a bit more it evens it out until the next bit breaks off. Does this sound feasible or does it sound like complete and utter balls?