Hi,

1999 E150 4.2 V6... some background...it has a bunch of ham radio equipment in it. Before I bought it, it probably sat for weeks at a time quite often, possibly months. I discovered it leak fuel from top of tank, probably filler hose because I see it is fuel stained. It smells of fuel when full. However it ran fine for hundreds of miles before I discovered this issue. I was running it out of fuel to drop tank when all of this started. I tend to give new to me vehicles a 500-1000 mile test just observing before I do anything to it, unless it is in immediate need of something. Within this range is when all this developed.

Ambient temp 75-80F, good crank, no run with MAF plugged AND NOT, tried starting fluid and got more 'backfire' popping type leans misfire style combustion.

This is the 3rd or 4th run in 5 miles after the van was completely normal other than a fuel related carbon coated #1 (passenger front) plug. It ran smoothly with a very occasional miss, prob from that plug. The plugs and wires are new. The poor cold start and run seemed to improve slightly after plugs and wires, but still rapid decline in overall situation since.

The first cold start I had an issue it set a PO301 code for #1 misfire within 30 seconds or so of starting. I have never seen a code again for anything, even while running poorly with low power even if running fairly smoothly, pinging sets in at moderate load and low coolant/air temps. Everything points to lean. The MAF was cleaned 500 miles ago...with the dedicated MAF fluid. Its not running like a bad MAF, I have felt that in a gas and diesel vehicle and both were much worse running than this. Besides, it seems to be 'not running' with minimal combustion while cranking with or without the MAF plugged in.

Fuel pressure is 30-45 on a gage with me in the driver seat with doghouse off. I initially thought I had hurt the fuel pump after running out of fuel. Now I am not sure I ran it out of fuel. I parked it in the driveway nose up after running just fine when all this started. I thought I had hurt the fuel pump after running it 'dry' or nearly so while cranking out of gas. Now fuel pressures don't seem to indicate a problem. pressure goes up with load and vacuum drop, sets at about 32 at idle....the last time it did.

I also changed both upstream O2 sensors with new Bosch, even though again I didn't think it would do anything. It didn't I kept the old probably perfectly good ones.

Kind of puzzling it can run as poorly as it has the last few times it has with no codes setting. I cant check egr other than I guess trying to pull a vacuum on it and seeing if it holds while the engine isn't running. I pulled the wiring plug on the rectangle egr control box with the two vac tubes running to it...no apparent difference.

Any thoughts, questions?