4.0 long crank then high idle...help

This is a recent problem. My 99 xj will take quite alot of cranking to get it to fire, the it will start to have a misfire. After a few blips of the throttle it's fine, but then it will idle at about 1100-1200rpm the rest of the day. I put in a tps about 1000 miles ago, and cleaned the iac and throttle body about 2 weeks ago. It doesnt come up with any codes either. Any ideas?

Sounds like you might have a Vac leak, and a faulty fuel pump check valve.

You might have a battery/electrical issue.

Clean the main cable ends at the battery, starter, block. Check the static voltage between the terminals--12.5 would be about right. Start engine, check the voltage between the terminals again--13.5 to 15.5 is what you are looking for.

If possible, have the battery load tested with a carbon-pile tester. Should hold 1/2 of the CCA rating for 15 seconds no lower than 10 volts. If it won't do that, replace it.

My suspicion is that the battery voltage is dropping to low and wacking the PCM memory, leading to the roached idle.