Hello! (new so hope I'm posting tech help in the correct place) I have a 2000 montero sport 4x4 xls 3.0, has around 96,000 miles has been in two shops with no luck and been down over a year at this point.. i really like it but it is having a problem that no one can seem to identify. It starts and idols perfectly and sounds fine but when you push the accelerator it will barley pull out of it's own tracks (sputters) but once you (eventually) get up to speed it runs fine as long as it's not under a load and on a level road. this is what has been replaced: fuel pump, fuel filter, fuel lines, injectors have been pulled and cleaned, new exhaust with new converter, mass airflow, crank pos sensor, cam pos sensor (diagnostic pointed that one) all timing components new, plugs and plug wires.. and some other things I'm sure I'm not remembering rite now. nothing has helped one bit, both shops are stumped and diagnostic computers are showing no problem whatsoever with it other than the cam sensor that was replaced. the fuel pressure is good, also did a compression test that showed all good so I guess that rules out valve problems or rings... I'm really lost as what to do at this point I'm too much into it to give up at this point. the shop I have it in now has all but given up but they are convinced it is fixable without anything major?. they are a reputable "import specialist" and pretty much the last option other than the scrap yard (UGH) .... thanks again and any input will be greatly appreciated

 

I had a similar issue with my '99... The truck would bog if accelerating hard from idle. Unfortunately, I don't know exactly how I fixed it as I did a lot of work all at once. I noticed you didn't mention cleaning anything on the throttle body or intake manifold. These were filthy on my truck and were in desperate need of attention. I disassembled & cleaned everything in this area as well as replaced all of the vacuum lines. (egr, solonoids, tps, idle control valve, etc.)

How far forward did they replace the exhaust? On mine the flex coupler had completely separated and the connections from the exhaust to the manifolds had both been leaking. I welded a new flex piece in and changed all of the gaskets. The local shop wanted $120 for the job and in retrospect, that was actually a pretty good deal.

Anywho, thats what I did on my truck (along with new plugs, wires, timing belt) and the truck now idles and accelerates properly.
-sj

BTW, I would recommend disconnecting the battery for 15min or so after any work so the computer will be forced to recalibrate. Good Luck!

 

what is your fuel pressure ????

 

the exhaust is all new including the flex coupling. could very well be vacuum lines though, I'll try that next, thanks for the reply

 

I called the shop and asked about the fuel pressure and they said that it was "within specs"