I bought this jeep with quite a few problems on the side of the road. That in itself was a mistake but I have soldiered through fixing everything possible. We have done many sensors (Crank, O2,etc) and we did a starter because the fuel pump died and we kept trying to start it on a slow cranking starter as it was. BUT the largest problem by a mile is that this is the small 2.5L 4cyl and it sounds like a DIESEL, when its cold it just pulses and runs somewhat normal, but once it warms up the RPMs start pulsing and dropping and it sounds like a god damn Mack truck. It goes away at high RPM but at low it is ridiculous. Does anyone have any ideas on what it could be? My friends say it could be valves not opening or something out of alignment. We had to up the idle to stop it from dying coming up to stops or just flat out stalling.