Paul in Houston TX wrote:
> wrote:
>> 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 choice but I had no where
>> else to put it. There are a couple of things that you should know about this van. First
>> it was not started during the three years that it sat on my lawn. Next it presently has
>> a full tank of 87 octane gas that I stupidly put in three years ago before I parked it.
>> The battery of course was completely dead. I charged it at three amps for two days and
>> quite 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 engine seems to
>> idle fine. if you goose it it seems to rev fine too. As soon as 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 constantly and eventually stays on and when read
>> it's a "random misfire" code 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 dies on the hills.
>>
>> I've gotten all kinds of opinions as to what this could be. Of course the gas was one
>> thought. But if it was the gas would it idle fine in neutral with no load initially?
>> I've also heard plugs was another thought. But again if 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 problem. Does anyone have any thoughts on what this might
>> be and what steps I might take to isolate it. Thanks very much for any help. Lenny
>
> Clogged fuel filter, failing fuel pump, clogged cat.
>

Filter, pump and bad gas are all possible causes. I would bet on bad gas
and filter though. MAF isn't the issue.
The idle in neutral doesn't mean anything, that engine will idle just
fine when it isn't under load. Put it under load and it needs more fuel
but it's getting crap = no power.

Drain the tank, you can jumper the pump and use it to push the old fuel
out once you disconnect the fuel line. Replace the filter and fill with
clean fuel. Bet the problems go away.

--
Steve W.