I have a 99 ford ranger with the 2.5L engine. The truck is difficult to start when it sits over night. The truck will start and the abruptly stall. I have gotten the truck to run by giving it gas and running it about 1500 rpm. The truck is perfectly fine after about 2-3 minutes of doing this. The truck will idle normally after this 2-3 minute period. Once the truck is warmed up you can shut it off drive it and it dosen't stall after its warmed up. The truck can sit for a couple of hours and start back up perfectly. The problem does not happen every morning though. The truck has 50000 miles on it. The check engine light does not come on when it is hard starting or at any other time. I put new plugs and wires on the truck after it started having this problem. This still did not help the problem. Please help
Pull the codes, there may be a 'pending' problem. CHeck the ECT & ACT sensors. The ACT is Air Charge Temp, so if it thought the air was warm coming in, it would not do the high idle & richen functions.. Same for ECT, engine coolant temp. These function to let the ECM know that you need bumped idle & slightly richer fuel mix.
If you are not even getting a bumped idle, when you used to, I'd be checking the ECT more than ACT, but it could be the IAC-Idle Air Control, too.