hoodster

hi everyone was wondering if anyone could help.. i have a 97 jeep grand 4.0 and sometimes it doesn't idle in cold weather (-10 celicus) but other times its fine and idles when its the same temperature . its been doing this every winter, maybe 20 times in total in 2 years. it started fine last night but, 12 hours later when i went to start it in the morning it just didn't want to idle on its own!! . about 6 months ago got a brand new distributor, new starter, wires and plugs and battery so those shouldn't be the problem..

heres what happens:

it will turn over but it just wont turn the engine.. the engine will start only if you pump the gas and keep your foot on the gas above 500 - 750 rpm and it runs nice and smooth.. i kept on the gas and idled it at about 1000- 1200 rpm for 5 min and it still wont idle on its own and stalls once you let your foot off.. also another thing is if you take it for a 20- 30 minute drive it will idle on its own fine and start back up no problem

i checked the battery its around 12 volt. checked to see if the fuel pump comes on it does.. theres some premium with regular gas in the tank with methyl alcohol in it and the tanks 3/4 full so it shouldn't be fuel or lines.. i plugged the block heater in for 4-5 hours and still wont turn it on so it is none of those things..

so was wondering if anyone else had the same problem and knew how to fix it.. i read similar threads on here, some were kind of similar and mentioned something about a ECM .. is that the computer or something? they also mentioned maps,a cam sensor, and a crank sensor and stuff but i dont know how to test them or where they are located. also is there a sensor for idle or that contols idle?. this is my first jeep and vechicle so im just finding out where all this stuff is and learning about it

any help is apprecitated
thank you for your time