We seem to be unable to find the reasons for the engine shuddering at sudden acceleration. Any ideas would be appreciated.
thunderbolt,
Mar 5, 9:47am
Is the engine still running on all cylinders when it is under load!
diweng,
Mar 5, 10:08am
I assume so Thunderbolt; I forgot to add that we changed all 6 spark plugs and that made the engine idle run much quieter and smoothly; Traveling gently the car responded fine (which makes me think all cylinders are running fine) but any harsh acceleration cause it to cough before catching speed. Even on low gear it works fine apart from the abrupt acceleration periods. Then we took it to the Mitsi garage and they checked for 2 hours on the computer and couldn't find any faults (over $200 thrown into the garbage ;op). Later the oxygen sensor was replaced too and for a new unit, since the guys from the garage said it was o.k. but they didn't know for sure. (go figure). BUT the fault remains the same.
Forgot to add it is a 6 cylinder 3 litre sedan.
edangus,
Mar 5, 10:13am
Cat Convertor!
andrea_w,
Mar 5, 10:20am
That does sound like it's missing - under load. I'm not sure what ignition system your car runs, but if it's coil packs those symptoms are pointing right at a faulty coil pack
phillip.weston,
Mar 5, 10:33am
is it GDI!
andy61,
Mar 5, 5:54pm
Is it the engine shuddering or the auto shuddering!
monte76,
Mar 7, 9:31am
bad torque converter lock up clutch, see a trans shop they should be able to diagnose with a quick road test.
mizkfc,
Mar 7, 8:49pm
i have this problem also with my mitsi legnum its tiptronic and shudders in third sometimes when its in auto but if i change it into tiptronic it stops. im trying to ignore the situation as iv only just bought the car lol
studio1,
Mar 7, 9:02pm
That's what ya get for buying an M car
m16d,
Mar 7, 9:11pm
Sure its not an auto problem.! Had one once that shuddered because a vacuum leak was causing it to jump back and forth between 2 gears. Mitsa dealer should have found that on the computer if he knows what he's doing.
lyonruge,
Mar 7, 10:14pm
Had a few with torque converter shudder, mostly smooth acceleration through 90-110kmh
diweng,
Mar 8, 2:38am
OK; I haven't been able to get much info about the car besides what is already said here. When saying that the engine "shudders", I mean that it hesitates (similarly to a chainsaw when it is far too lean on the low adjustment). So if the acceleration is progressive, it behaves well and smoothly; but if the acceleration is sudden then it coughs as if it was choked, specially when it is after a full stop i.e. parking or a traffic light. Cheers
diweng,
Mar 8, 2:41am
Forgot to add that we have no clue if it is a GDI and no idea how to deal with "bad torque converter lock up clutch", what to look for, what to inspect, clean or change. So any help with these would be great. Cheers
timmo1,
Mar 8, 6:49am
I'd be picking leads or coils.
phillip.weston,
Mar 8, 7:13am
yeah it doesn't sound like the common torque converter lock up clutch shudder which is a faint to pronounced shudder at 50-80km/h in top gears. This does sound ignition related or perhaps even fuel system if it's a GDI engine. GDI will usually have GDI badges on the bootlid and on top of the engine cover.
diweng,
Mar 13, 1:29pm
Thanx: the question then is if it is leads or coils or even fuel, why then the Mitsubishi garage did not pick up the fault thru the computerized apparatus! It is not a joke to throw away about $250 for a second guess. Where would U guys suggest I start checking while at home! or is there any website that has info on these issues! Cheers
diweng,
Mar 14, 11:45am
Checked the engine today and found no indication whatsoever about it being a GDI. Cheers
m.g.p,
Mar 14, 10:03pm
This is a typical Mitsi problem The computer forgets what its doing Take it to Mitsi get them to reboot the computer and retime the engine
diweng,
Mar 16, 8:24am
Thanx m.g.p; It was my mate who took it to the Mitsi garage so I don't know exactly what they did but I'll check about that. Cheers
diweng,
Apr 22, 6:25am
Thank U all for Ur patience but the condition of the said car is getting worse week after week. Any further suggestions!
beast9,
Apr 22, 6:41am
does it have high tension leads or coil packs if its leads get a digital multi meter and set it to ohm's and check each lead so for a 4" lead 1k is alright 2k+ is bad and needs to be replaced also try changing your air filter and fuel filter
hondalova,
Apr 22, 10:14am
them mitsys have IIR 3 coils at front at 3 leads coming off the coils going to the rear head. checked AFM, TPS or the coils themselves!
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