So my jeep tends to run fine sometimes, and other time it runs at a 1000 rpms, sucks for air, gas up and bogs then dies. I have cleaned the throttle body, replaced idle solenoid, and throttle position sensor. After sitting for 30 minutes its usually fine. It has a rough idle occasionally and gets horrible gas mileage. My fuel rail pressure is good, and the pump/regulator/filter was replaced in July. Could it be an intermittent map sensor, or my fuel filter affecting it?

 

*Tuneup hardware review. When was the last time it had new spark plugs, wires, cap, rotor?

*Was the fuel rail pressure verified with a gauge? Gotta do it that way. With a 99, it should be 49 psi, plus or minus 5 psi.

*High idle can be a vacuum leak. Perform a comprehensive search for one of these.

*Map sensor can be tested with a manual and a meter.

 

To add to this have you had it scanned for stored codes, also search for " heat soak TSB" most affected are 00-01 models but 99s also are under this as well, its due to heat soak of the injectors. Is this condition random or can it be pin pointed to certain circumstances? If it can be duplicated you might put the fuel pressure gauge on then and see results.