Have an 05 caravan that is possesed! Replaced the short block and used my heads(reworked),upper and lower intake, replaced all external seals and gaskets, dropped it back in and hooked up everything carefully and now it won't idle more than a few seconds until the engine just starts to warm up, guessing the O2 sensor heaters kick in and then it begins to drop the rpms to nearly zero then surges to about 1500 then does down again til it finally quits. Also after driving about 2 minutes it begins to buck and stumble at 55 mph then it acts like it is starving for fuel and no power at all, can't get it above 15-20 mph. HEEEELLLLLPPPPPP!!!! what an I missing?

 

Judas Priest was always motivating for me in the background. Besides that, have you been able to check your pressures anywhere? May need more information to help?

 

Fuel pressure checked just before the fuel rail. The book calls for 58 pounds +/- 5 and that is exactly what I have, 58 pounds. Removed the pump to check the pick up sick and the fuel filter is in the pump. Blew back through the filter and it was clear, and volume is good, what time I have gotten it to half way idle the vacuum is about 19 1/2 inches. I have replaced the coil pack with a known good one, no change. New plug wires and plugs. No leak down on the cooling system, held 20 pounds pressure for 10 minutes. New thermostat and ext sensor. Also changed the throttle body, iac and rod with known good ones, no change. Have gotten a P0171 code, sensor 1 bank 1 detects a lean condition but if it runs any time it smokes black out of the exhaust. Took the exhaust loose at the manifold to check the cat for restrictions, no change. Checked and cleaned all grounds and added additional ground strap from engine to the body. Ckp replaced, cam position sensor checked good. Sprayed ether around lower and upper intake and intake hose from filter box, no change in rpm. New air filter, cleaned air intake sensor. checked all wires from sensors/ power distribution box for resistance/continuity all showed fine. 5 volts at sensors on one side, good ground or continuity back to ecm. Her was bad, replaced with new oem. Took apart power distribution box and cleaned the connectors and pins thoroughly, also at the ecm. Don't remember if I stated. This before, 3.3 and 4 speed trans with 135000 miles. Fluid and filter change on trans. Compression check shows all cylinders between 185-195. New pcv valve...what am I missing?

 

Also replaced up stream O2 sensor

 

Time to trade it in on a new one...