Mechanics

INITIAL SHUDDER WHEN COASTING.

2004 Mitsubishi Magna • 6 cylinder 2WD Automatic • 75,000 miles

Hi guys,
I have a 2004 Mitsubishi Magna with a 5spd auto transmission. It's done approx 75,000km (47,000 miles) and up until now it's been fine. About 3 weeks ago I started noticing the gear changes becoming harsh****** and since then it has started shuddering when I take my foot off the accelerator. I notice it most in 3rd gear around 60kph (35mph), but it does it in all gears. It only does it initially when my foot comes off the pedal and then it smooths out again as the revs drop further. Today I did some maintenance which included: Oil change, oil filter, fuel filter, air filter, and fuel system treatment additive which is meant to clean injectors and such, and I sprayed throttle body cleaner in the throttle body and in the idle speed controller section. I then took it for a 20min drive and it's still doing it. I didn't expect it to be fixed, but if you can help me out and give me a suggestion or two that would be much appreciated.
Thanks heaps in advance.
Simon : )
Brisbane, Australia
Avatar
Prodders
April 8, 2011.



If you use a rubber mallett you'll find hrat shield problems easier. Worn engine bearings can be noisy until oil pressure builds.

Merlin2021
Apr 8, 2011.
Your answer has nothing to do with my question. Please re-read my question.

Tiny
Prodders
Apr 8, 2011.
Sorry that answer was suppsed to go to a different question, obviously! Your problem may be due to either a sticking servo piston, or dirt in one of the valves in the valve body, have the transmission fluid changed with th pump station machine as this uses fluid under pressure and cleans the transmission. Also have a look sy engine and transmission mounts. If its more like a bucking feel, check the MAF(mass air flow) srnsor.

Merlin2021
Apr 8, 2011.
Thanks for your reply. I've checked the engine mounts and they are all look in good condition. Not sure how to check the MAF properly, but I tapped the top of it while the eingine was running and the engine didn't miss a beat (I saw this basic test in a video online). I'm now guessing it's a transmission problem so I will head down to an auto specialist tomorrow for them to have a look. Will let you know what the outcome is.
Thanks again : )

Tiny
Prodders
Apr 10, 2011.
Ok

Merlin2021
Apr 11, 2011.
Hi Simon from Brisbane,

Did you find the answer to your problem? My 2004 Magna has started shuddering around 1500 revs and before I take it to a mechanic I would like to know if I can fix it.

Cheers,

Claire

Tiny
Claireporter
Aug 27, 2012.
Hi Claire,

Unfortunately I haven't been able to locate the problem. I've done 2 transmission services (pressure flushes & oil changes), changed the idle speed controller (idle speed valve), and changed the throttle position sensor, all with no success. It's a very weird symptom and at this stage I just can't afford to keep spending money on it, especially with no results. I'm now thinking it could be something to do with the fuel pump, but can't really afford to get it looked at.

Can you describe your shudder in any greater detail? Does it shudder when you are accelerating or when you take your foot off the accelerator and coast, like my car does?

Cheers
Simon

Tiny
Prodders
Aug 27, 2012.
Hi Simon,

My foot is on the accelerator resting to keep it running at the current speed limit (between 60-80). I will lift my foot off lightly when the shuddering starts, then bring it back down which stops it. The shuddering only starts shortly after I have been stationary then accelerated to 60-80k's. On the highway at 110k's it is fine, humming even.
I have it booked into the garage tomorrow morn, fingers crossed he can help me out. Will let you know.

Claire

Tiny
Claireporter
Aug 28, 2012.
Hey Claire,

I'm no mechanic, but two things I think it could be are either a dirty or faulty idle speed valve, or a faulty throttle position sensor. But again, I'm no mechanic or expert, I have just read that those faults can cause problems like that. I hope the garage can find and fix the problem with minimal expense : )
Let me know how you go.
Cheers
Simon

Tiny
Prodders
Aug 28, 2012.
Cheers Simon. Took it for a drive this morning with the mechanic who thinks it's the drive shaft. Booked it in for next week so will update if it fixed it or not.
Minimal expense and the Magda do not really bind well. My fingers are crossed too.
Cheerio,

Claire

Tiny
Claireporter
Aug 28, 2012.
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