SOLVED: 3rd gen transmission stutter and momentary loss of power

[tj90]

Just got back from mojave road with 03 limited. Awesome adventure and truck did great. As you guys may or may not know, I've been dealing with momentary loss of power especially when truck is been running for a few minutes. I've dinner so much entune stuff etc, I was at a loss why this was occurring. Truck ran great on mojave for 2 days straight. We hit rain going back to san diego and stuttering happening again. Truck did it in 2w and 4wheel high. Tranny was doing it in 5th gear with no shifting. I thought it was the actually the actuator or shifting since it normally happens in morning leaving the neighborhood. Now that it did it going down the highway at 65 mph with no shifting, I'm wondering if it's a moisture or cold thing.

I'm going to clean and inspect all connectors under the truck and hoping I find the culprit. Are there any problem connectors that are documented?

 

[ChrisCosta416]

Have you changed the transmission fluid and filter? If you haven’t be sure to use a quality filter and only Mitsu SPIII OEM fluid or equivalent

 

[tj90]

Yes. I was hoping it needed fluid or filter but changed it with spiii. No change. I've replaced the intake upper and lower, cracked exhaust manifolds, tune up stuff and it still happens. I dont think it will leave me stranded...

 

[ChrisCosta416]

Have you tried cleaniNg the throttle body

 

[Inyo_man]

Have you checked for codes?

 

[tj90]

No codes on obd and throttle body was cleaned and electric actuator was replaced with another from scrap yard...

 

[Michael Brown]

ALso check for correct vacuum line placement and leaks. This caused poor performance in my 01 until the engine would warm up

 

[tj90]

I think I solved my problem! I bought an Ebay MAF for $45. Bolted it on and it's like a new truck! What gave me the clue was this weekend, the truck was stalling completely out. It happened after cleaning the MAF with throttle body spray. I figured the spray made it worse. It was bogging down at stop lights and when cold, the truck was bouncing between 300 and 1k rpms. I watched a you tube video that talked about probing them for voltage and how a car will run with it disconnected. I did that and actually the truck ran better in "open loop".

I checked my maintenance logs and I had an entry from 2016 that said that my truck would stumble if I knocked the MAF housing with screwdriver handle. I guess it was marginal enough to keep running all these years. I'm wondering now if some of my emissions problems are due to MAF and not worn rings or valves. I wish I replaced that part 3 years ago at the first sign that something was wrong with the MAF!! Time will tell if this is the fix. Thanks to everyone for your inputs!

 

[SONICMASD]

I think I solved my problem! I bought an Ebay MAF for $45. Bolted it on and it's like a new truck! What gave me the clue was this weekend, the truck was stalling completely out. It happened after cleaning the MAF with throttle body spray. I figured the spray made it worse. It was bogging down at stop lights and when cold, the truck was bouncing between 300 and 1k rpms. I watched a you tube video that talked about probing them for voltage and how a car will run with it disconnected. I did that and actually the truck ran better in "open loop".

I checked my maintenance logs and I had an entry from 2016 that said that my truck would stumble if I knocked the MAF housing with screwdriver handle. I guess it was marginal enough to keep running all these years. I'm wondering now if some of my emissions problems are due to MAF and not worn rings or valves. I wish I replaced that part 3 years ago at the first sign that something was wrong with the MAF!! Time will tell if this is the fix. Thanks to everyone for your inputs!

That makes sense because the Montero uses a different kind of MAF than most other cars. It is a Karman Vortex MAF and should never ever be cleaned with traditional MAF cleaners or the risk of damaging it is very high. It really never needs a cleaning since it operates completely differently but if you absolutely have to clean it I've heard CRC Lectra-Motive is safe.

 

['round n' back again]

ditto on cleaning.
it's an electrical item and must be treated as such.
lesson learned.

 

[Michael Brown]

Good to hear that it is running again.

 

[tj90]

Yeah, it feels good solving that issue. I really like the truck, so I'll try to keep her going!