Have a serious problem with my 92 Explorer. Just put a new engine in about 6500 miles ago. Up until 2 weeks ago everything has ran fine. Two weeks ago my check engine light started coming on and the truck started to run rough ( idles rough and flutters at cruise speed- -also tries to die first thing in the morning). Also starting up in the morning some times it would just spin over but wouldn't crank until I turned the key off and tried again. Now it has started to blow the vaccum lines off. After it gets warmed up and I drive somewhere and shut it off, it tries to only spin over 1 revolution and stop, try it second time same. 3rd or 4th try it will crank. Acts just like low battery. Changed Battery, solenoid and starter but to no avail (Starter was dragging). Took to Autozone to have codes pulled but they had lost scanner. Bought one and only got o2 sensor code (guessing from maybe to rich mixture with timing off). Part guy at Autozone said reason it was slow starting was timing was off. Since this is a distributorless ignition how could this be? Brand new motor with all new timing components installed. Doubt it has jumped time. Would like some opinions before I go replacing the EDIS or the Computer. Thanks

 

If you go to the trouble of checking the timing on your engine, check out my thread under the 2.8,2.9,4.0,... forum. Title is about the timing being 180° off. The "harmonic balancer" can slip relative to the crankshaft and give erroneous timing readings.
If the timing really is off, I'd suspect the crankshaft position sensor, because that's where the PCM gets the information for the base timing.
However, I'd start by checking out that O2 sensor code. Which code was it? Was it a KOEO, continuous memory, or KOER code? One of the first tests for an O2 sensor code (after verifying that the O2 sensor is good) is to check the fuel pressure. Check that as well.

 

Thanks mr shorty. I changed out the pick up sensor on the crank this afternoon and that did not fix it. I do have another pulley off an old engine that I was going to rebuild before getting this engine. The code I got was a 173 (I think, 1st time ever trying to use scanner) it was stored in continuous memory (2nd series after the seperator.) it was key on engine off. As far as fuel goes. I dropped tank last weekend to fix fuel guage. (found float cracked) went ahead and put in new pump and sender and filter. Problem I am having was happening before this. I thought maybe that might have also been my problem, but still having it after pump change. Haven't check O2 sensor yet because pipe and resonator behind muffler needs to be replaced and was going to do it all at once.