Three years ago at the state auction I bought a 2006 Chevy 3/4 ton van with a 4.8 engine.It was in real nice shape and at the time I didn't need it so it has been sitting outside in my yard. I realize this wasn't the best cho ice but I had no where else to put it. There are a couple of things that yo u should know about this van. First it was not started during the three yea rs that it sat on my lawn. Next it presently has a full tank of 87 octane g as that I stupidly put in three years ago before I parked it. The battery o f course was completely dead. I charged it at three amps for two days and q uite surprisingly it came back up and cranked the engine. The truck started right up, another surprise.
The problem is when you first start, except for a very slight shake the eng ine seems to idle fine. if you goose it it seems to rev fine too. As soon a s you shift it into drive though the RPM's slow way down, the shaking gets much worse, (the engine even stalls sometimes) the "engine" light blinks co nstantly and eventually stays on and when read it's a "random misfire" cod e set on the OBD..g. I took it out for a short run today. It seems OK on the flats but acceleration is "bumpy". It is missing and it really almost d ies on the hills.
I've gotten all kinds of opinions as to what this could be. Of course the g as was one thought. But if it was the gas would it idle fine in neutral wit h no load initially? I've also heard plugs was another thought. But again i f it was plugs same argument as the gas? Then there is Mass air flow sensor , vacuum leak fuel filter etc. I hate to think about shotgunning this probl em. Does anyone have any thoughts on what this might be and what steps I mi ght take to isolate it. Thanks very much for any help. Lenny