I have a 1998 E-350 Cut van with a 5.4L engine. It's been running really bad. No power, not running on all 8. Anyhow, check engine light was on till I replaced the plug that it said was bad. #3, hardest one to get to (except # 8 & 7). So I get that one replaced and the engine is still running bad and there is No check engine light coming on. I suspect it is vacuum related but not sure. Wants to die when put in reverse. That has to be vacuum related doesn't it?

Thanks in advance!
GFen

 

What would be different manifold vacuum-wise when the truck is in reverse as opposed to drive?

 

I don't know Tom. That's what's puzzling. What else would make the engine run worse when put in reverse?

 

I can't think of much, but how does it run when you're in drive? Perfectly normal or just not as bad as reverse?

 

Have a look at my pics and see the vacuum line that broke on mine. Link below. Caused similar issues.

Ford Truck Enthusiasts Forums - PStruwing's Album: Broken vacuum line

 

PStruwing, I think you may be on to something there. Got to wait till Monday to check it out. Does that hose just plug into the back of the intake manifold? I tried to unplug it but it didn't want to budge and I didn't want to break it. So you say that goes to the egr valve? I thought it was a pcv valve and replaced it with a new one.Am I wrong there? This engine is the hardest to work on that I've ever owned.
And Tom, no it doesn't run good in foward just not as bad. The tranny does use vacuum to shift, that's why I questioned whether it was something vaccum related.
Anyhow thanks folks
GFen

 

If you look at the second picture you will see the port it plugs into, and crack in the tube.

It is simply pull-off push-on!

 

I checked the vacuum line that goes to the pcv and it was cracked so I replaced it.
Ran better at first but when warmed up went back to running badly.

Still, getting no codes! The check engine light should have come on by now!
I'm about ready to drive it into the lake!

Is there a diagnostic computer that I could hook up that would give me some answers? How about Auto Zone, can they do that? I have a code reader but it's not doing me any good right now.

Thanks Guys for your help.
GFen

 

That's real strange that it wouldn't even give you a P0300(random misfire) code. Could it be something that occurs when it switches into closed loop?

How many miles are on it? Have the COPs ever been changed? Feel like a blind guy trying to find a sandwich in a gymnasium here without any codes...

 

I've only got 132000 miles on it. Never have changed out the COP's . But there's codes for all of that. Maybe I'm just relying on the pcm too much.
Hmmmm! dammit

 

True, but there should be codes for just about any time there is a consistent misfire...

 

Hopefully not too dumb of a question but is the CEL bulb working? The easiest test would be it's illuminated when key on, no engine running.

As Crazy001 says there should be a code of some sort--misfires or vacuum issues tend to trigger the MIL or Check Engine Light.

 

Something I did being before was high pressure wash the engine and water got into the cops causing issues with no codes. Pulled them to dry them out and found one with a cracked insulator. replaced it and all was good.

I installed a set of higher voltage eBay COPS and they have worked great for almost 50k, I kept the Ford COPS just in case.

 

I've done the same thing, used Granatelli's though. One by one they've began to fail, conveniently outside the warranty period though! Weather permitting I'll be swapping them all out to my originals with new boots.

 

Thanks guys for helping me to figure this out.
Yes the cel bulb is working. Comes on when I first turn the key.
I was thinkin of changing the cop's. Found some on ebay. Set of 10, from uneeksupply for 99 bucks. Seeme kinda cheep to me. Now I'm BLUE.

Today is balljoint day on my wifes 97 Expedition. It's all fun, right?

GFen