So my montero starts fine if I drive it every day, but if I let it sit for a couple days it will has trouble starting. I'll give it some gas, then let it sit for a while, and then crank it over again and give it some gas and it manages to start. Once it starts it runs and idles perfect. Has anyone had a problem like this before and what should I look at replacing?

could leaking fuel injector(s). you can buy new or rebuilt. check rock auto.

UPDATE: Changed the fuel filter, but the problem seems to have stayed. It takes about one second of cranking for it to fire where as before it fired instantly. I do not know if this will help, but the engine does have 240k miles on it, is this a common problem for engines this old?

Where is chico ca? My bet is the engine coolant temp sensor for the ecu. If failed, the ecu won't supply cold start enrichment, and if ambient air temp is too cool, engine is too lean to start cold. Sensor point forward off water neck/ thermostat housing on front center of engine, has two terminals in a tee config, costs about 30 bucks. this problem causes an iffier start in warm weather, degrading with ambient temps as it gets colder out.

Next guess is water in the tank. Add a half bottle of drugstore rubbing alcohol to adsorb the water and burn it out the tailpipe.

Ok, that seems like a good idea. I very well could have water in the tank as I've been bashing through the mud and puddles lately. Also, it will probably be good to replace the sensor anyways.

Chico is about 100 miles north of Sacramento on Hwy 99.

theres a check valve that keeps fuel pressure up in lines, it may be that the check valve has gone bad and you're having to pressurise the lines. if you can put a fuel pressure guage on it and see if the pressure stays up, or if it continues to drop.

Exactly, I went through this in Montana. Doesn't hurt to go to a lighter oil for the winter, but Chico is a long way from the cold. Also, changing out the filter is good but there is a screen on the pump that basically disintegrates over time. But if it just cranks and seems like there's no fire it's a sensor issue.

Hi DJ,
My 89 3.0 is having the same exact problem....if you let it sit for more than a day it is very difficult to start. Once it's running it runs fine, temps aok and will fire right up all day long.....unless you let it sit for more than a day!

I did replace the engine coolant temp sensor and that did not make much difference, did not solve the problem! My engine is OEM and only has 120,000 miles...so not a mileage issue.....I'm up in Lake Tahoe in the snow and cold...and that doesn't help. This does not happen in the summer/dry months.

Just FYI: I have replaced timing belt, water pump, thermostat and engine coolant temp sensor. Engine passed Block test and compression test aok.

Would a bad check valve look like having to crank the engine/bump the starter 10-20 times to get the fuel to the engine? If it's a bad check valve why would it finally start at all??...and then run fine???

Update:
Still having a bit of trouble, but I know it is not any type of leak/check valve. In the morning, its about 30* outside and it will fire up in half a crank, but in the afternoon when it about 70* it takes a couple seconds of cranking. Replaced coolant temperature sensor.

Check the intake air sensor per the manual. It seems to be temp dependent. Other stuff to check after a hot soak by cooling one component at a time with an r134 spray, maybe dizzy, coil, coil doodads.

If it cranks in two sec, it's not a problem...