Significant lack of power...

[Thunderbear]

More so than can be accounted for in a tired 2.5. Refuses to go more than 15 mph up any hill. Idles okay, revs itself occasionally at idle. Cold isn't helping I'm sure. -10F.. Ideas?

[Dadinator]

could be a multitude of stuff.

 

Is the Catalytic Converter clogged? I had a car do that once.

 

Throwing any codes?

 

The more info, the better...

[Thunderbear]

No codes since it's the MJ, cat is new according to the previous owner, whatever thats worth. Not a bad idea, though, since it has the same problem in summer, just not as bad.

[Harley]

When was the last time ya fed the gerbil? Mine gets tired when I don't feed him regularly

[Pete M]

what's the fuel pressure? flow rate?

[1987Comanche]

Have you done a compression test? My '87 2.5 started losing power and it turned out it was also losing compression. That's why I now have the '90 4.0 MJ.

[txjeeptx]

Could be the fuel sat too long. This Ethanol junk they add to the fuel now separates out and sucks up water, fouling the fuel quickly, like in as little as a month.

 

Other than that, maybe fuel filter is in need of replaced, maybe there is a sensor going out or out of its operating parameters in the cold weather.

 

There's also a chance the engine sat long enough to have the piston rings get stuck/don't seal properly, losing compression, but you'd have bad blowby showing up as pressure in the crankcase/valvecover. Does it smoke much out of the PCV hole when you take it out while running the engine?

 

Also, with all inline engines, when was the last time you checked to see if the intake/exhaust manifolds are still bolted up tight. The bolts back off and cause a vacuum leak.

[Thunderbear]

Thanks for all the tips. Definitely plan on checking the fuel filter, and a compression check. The manifolds are tight for the first time in the life of the truck, I think. It actually has all the bolts, finally. Today it blasted through 18 inches of snow over and over as I barreled down my snowed in driveway. Very impressed, just irritated that I had to jump it when it has a new battery. Thinking about changing the starter, since is such a slow start...