wbrianr

Hood wasn't left open and the plugs were all Motorcraft. I also thought it was odd to get 4 cylinders misfiring at once, but it had been extremely cold and extremely windy to the point that I'm certain that the engine compartment probably had some snow in it. -- we'd had 30mph winds and blowing / drifting all weekend. ---- the thing that was throwing me was that it wouldn't start after sitting for a few days. --- I'd been driving on the same gas for a couple days, so I think it's okay.

I replaced the IAC 2 or 3 weeks ago after having a few starting issues and I hadn't had a problem out of it since then.

Perhaps I'll replace the EGR valve just to be on the safe side.

fordforlife0225

Glad it's running well. I know after I changed my plugs it was rough at first start up but ran great after that. As mentioned though it's weird that all those COPs would go at once.

gator0308

Maybe intake starting to leak coolant in the cylinders. I know I had to replace mine just a couple weeks ago. Right after this cold snap hit.

Jbrew

I don't think you ever got around to checking the fuel pressure did you? Even tho you proved the pump to be working, they usually get weak before failing.

Pump life on average is 90,000 miles. So your getting close. I'd still try to test it. 29 lbs is minimum, but on the weak side.

wbrianr

thanks for the tips! I'll see about getting the fuel pressure checked.

FWIW - it started right up this morning after sitting out all night and ran smooth all the way to work (about a 40 minute drive).

wbrianr

Follow up:
This morning on my way to work, the truck missed a little bit and the SEL came on again (not blinking, though). It settled down and seemed to be running okay, so I continued on to work. I had the OBDII reader with me so I checked it when I got to work: P0303 (#3 cylinder misfire -- not one of the previous ones I'd replaced). I erased the code. At lunchtime, I drove the truck to the bank and at stop lights I could feel it miss just a bit occasionally, but the light didn't come back on.

I've ordered 4 more coils / plugs (I probably should have just replaced them all anyway -- I think #2, #3, and #5 are originals), and I have a fuel pressure test gauged ordered that should be delivered today so I can check the fuel pressure.

On a side note: weather conditions this morning were very similar to the conditions when I had the first problem (below 15°F and after a day of blowing snow) and the SEL came on within 1/4 mile of where the SEL came on the last time. In both cases, I did not let the truck warm up before leaving. -- Essentially started the truck, backed out of the driveway, and headed to work. I wonder if this could be cold air related / moisture related in some way.

Anyway, I'll report back on fuel pressure when I've read it.

wbrianr

So the fuel pressure is reading right at 30psi while running. --- Fuel pump problem?

NOTE: I tested this with an Actron CP7818 gauge attached to the schrader valve on the fuel rail. There was no pressure showing prior to starting the truck even with the ignition turned on and fuel pump primed.

wilson84

Check the IAC valve it will.make it run.crappy

wbrianr

I replaced it a few weeks ago.

Jbrew

That's probably it, - pumps dieing or there's an internal leak. When the pump charges the line in run, it's @ partial pressure. It doesn't finish until you start it. So, you should read something on the gauge... When you test that, position the gauge so you can see it from inside the cab. So you can see if it jumps quick, - w/KOEO. Cycle the key quickly three times or so and watch the gauge.. What's happening?

Also, how did the pressure test without vacuum ? The FPR check out?