My 1999 jeep grand cherokee is slow to start after sitting for a hour or so

Sounds like the solenoid................it gets overheated, when it cools off it'll start and run again, get heated again, shutdown.

I have a 99 jeep myself and it was my throttle position sensor.

Hi, i have a 1999 jeep grand cherokee, 4.0 litre, had the same problem, quits running out of the blue, driving down the road, or sitting idling. starts right back up or takes some cranking to get it running. found out that the crankshaft position sensor was going bad, cost 40$ for the part, but had to have mechinac replace it due to it's location, hard to get at. jeep runs great now.

Your crank sensor might be the culprit that's causing your problem. Have it checked.

sounds like it time to have the front end balljoints inspected. Only with an inspection will you get the proper results. Why guess, this is a safety issue.

Change spark plug with NGK

Have the tranny checked out.

Starter...if the starter is old, it is getting heat soaked. Replace the solenoid.

I'd suggest the ignition control module, however I'd have a certified mechanic check it out just in case...

This same thing happened to mine. It only happened in really cold weather though. I added a few inches more of coolant into the overflow. It fixed the problem. I also discovered if that is not the problem, the sensor in the overflow can go out and a replacement is about 20 bucks.