Newbie at this but hope forum members can assist an ol fart with his toy... the Sport.[/align]Will let go of my sport when they pry my cold fingers from it along with my pistola.[/align]Anyway.[/align]Problem is as follows.[/align]Montero Sport 2000 89K, 3.5 automatic 4wd Limited.[/align]Engine misfires bad on when downshift of transmission from over 2 k to around 1400 and ride appears as if I were driving over a washboard in the road. (thats like close railroad tracks for the younger kids) a real chatter.[/align]Will not recover but ever so slowly to the 2k rpm and then smooth with no problemo.[/align]I have replaced, within the last week on dealers recommendation, The plugs-plat, Wires, 3 piece coil and running injector cleaner in the regular gas. Over 1 K cost and still the same problem. The TPS ( throttle position sensor) is OK [/align]Acceleration from start is great until down shift or slowing of the engine by a load like hill. As long rpm is 2 k or more everything works great. Mileage is at 18 so not too bad.[/align]Both myself and mechanic are dumfounded as to the cause.[/align]Its interesting in that the problem only immediately started to occur when I had the original gas tank replaced as the welded baffel had sprung a leak and seeped gas on the outside. Original fuel pump installed and new fuel filter. NO signs of gas deprivation when running at 2k plus rpm so feel that there is not a fuel quantity problem[/align]Absolutely NO dash warnings and computer for On Board Diagnosis is clean[/align]Any thoughts on this from brainstorming or your history would be greatly appreciated.[/align]OL Texan awaiting your speedy answers.[/align]Thanks[/align]

 

you need to flush your transmission using ONLY mitsubishi fluid.

you're suffering torque converter shudder due to worn out fluid, or the incorrect fluid.

 

Not wanting to go off topic here, but can Mitsubishi SPII fluid be used in place of Dexron III?

 

What speeds does this "missfire" occur? If you power brake the car will it miss?

 

Appears to be around 25-35 mph.[/align]When missing/shuddering the rpms are difficult to raise to 2k plus but will do very slowly.[/align]Am going to tranny specialist in AM for a torque converter analysis to see if its sticking (locking) causing a shudder.[/align]Will reply with the analysis [/align]Thanks all for now.[/align]Chapter 2 will follow in this a strange case.[8D][/align]

 

First, DONT go to a "tranny specialist". The only people that know mitsu trannies are mitsu techs. Ive seen more "tranny guys" screw up every possible part of trannie than you can shake a stick at.
Second, this has been talked about before on these boards.... It is a known issue for those that have either neglected their trannies, or used the wrong fluid. Get it flushed using ONLY mitsu fluid. Do NOT use anything else, no matter what anyone says is acceptable or not.


of course, you may in fact have a different issue. But I would kinda doubt it.

 

Not sure what you're asking.

Mitsu stopped using SPII a decade ago. and Dexron III (which is also long outdated) has NEVER been for use in a mitsu built transmission.

 

Sorry, I meant DiaQueen SPIII fluid. The owner's manual for my '00 calls for Dexron III, which is why I was asking.

 

if you have a full sized montero, the situation is a little different.

the 2000 would have been the prior year body-on-frame design, which did NOT use a mitsubishi transmission. Rather, they used Aisin-Warner transmissions. 2001 montero saw the use of mitsu sourced trannies.

The Aisin-Warner does specify dexron 3, but SP3 works fine in that trans.

 

Thanks a lot! I was wondering whether or not SP3 could be used.