Just picked up an 88 MM. Runs really rough.

I picked up an 88 off craigslist a few weeks back for scrap value. Body is mint (it's almost hilarious how flawless the truck looks while running so poorly), interior is nearly perfect but the engine is running really rough.

Timing belt went a few days ago which I had replaced so I am now $600 flat into this truck which I guess isn't too bad considering it moves at all.

Since I really don't know all the technical wizardry of how this stuff works I'll just explain what the truck is doing instead.

-Idles rough on cold start. Idle is also very erratic. Will smooth out then chug then seem to rev then almost cut off again.
-Has very little immediate throttle response on level ground and nearly zero response uphill where I am forced into excessive downshifting.
-After running for a few miles ( distance to work ) if I stop for gas it requires multiple attempts to get cranked.
-Is easier to get cranked when cold.
-I seem to be able to hear a "whiring" type sound that I cant decide whether it sounds like metal on metal or air whistling.

-Seems to be running too high an rpm pretty much all the time unless I am a gear above where I should be. For example, 45mph in 4th gear sounds like the engine is about to explode which leaves me having to shift up into 5th which then bogs down on anything except downhill grades.

So far from the "unpaid advice" I have had my problems are related to anything from a carb that needs to be rebuilt, slipping clutch, bad plugs/wires, vaccum leaks and valve damage from when the timing belt broke.

I don't have the tools or the knowledge to do anything on my own or the time to do it via manual assistance (work 70 hours a week) so whatever is fixed will have to be done by someone else. Just trying to educate myself on some of these symptoms so I can possibly avoid being bent over by a dishonest mechanic looking to sell my "i have no idea" self something I don't need and that won't fix the problem.

Truck has less than 100k on it which is the most frustrating part. Half of me thinks the engine is nearly done while the other half thinks I am a $40 part away from having it running right. :shrug:

If you don't have the time nor skills to do it, then take it to a reliable Mitsu mechanic and have them figure it out and give you an estimate. you will be better off.

You have been given all the usual suspects. you won't figure it out over the internet...but it could also be a clogged Fuel Filter :-)

I agree, clogged fuel filter and also a sticking EGR valve. You can do both of them your self. It's easy. Look in the manual section for your truck. In the 216 manual thread there is a book that covers your truck AND the Montero. But like LSR says it might be better if you get an estimate if you don't have the skill to fix it your self. These trucks will require you to work on them. It just part of the agreement everyone makes when buying a 30 year old truck.

I second the egr and fuel filter - also check the bolts on the intake, exhaust and carb holddown bolts - if they are loose they will cause these issues too.

Sounds to me like carb issues. Hard starts, down on power, etc.
I went the popular route, and did a Weber conversion. Huge help.

Whirring noise might be water pump / fan. I have noise in mine, and the water pump has more play then I would like. Great opportunity to go to an electric fan.