'99 fuel system

[mechanized]

Hello all,

I have a curious situation with my '99 Explorer 5.0 AWD. The truck idles great and cruises fine on the highway, but when you start to accelerate faster the truck stumbles pretty bad until you get the new cruise speed. I have changed plugs and wires but that didn't cure it. Is the fuel pump the culprit? Is the '99 a returnless fuel system? I have no ckeck engine lights. I have 221K on the truck. Thanks for any help

 

[Cobraguy]

Returnless fuel system.

When is the last time you changed the fuel filter?

If that doesn't fix it, have the fuel pressures checked when the problem occurs. Attach a pressure gauge to the schrader valve on the fuel rail and tape it to the OUTSIDE of your windshield. Drive it and record your pressures. Don't rely on scan tool pressure readings as they show what the ECM sees...not necessarily what's happening. (i.e. bad sensor)

 

[mechanized]

Ha ha, I don't think it ever has been changed. I'll do it if a part store is open, but doubtful today. Thanks for your help! Plus, I used to live in Phoenix for 5 years..........I'd move back in a heartbeat.

 

[Cobraguy]

FANTASTIC city! And it's a car lover's paradise. There are more exotic cars, hot rods, etc here than anyplace I've ever seen...including SoCal.

 

[dynamite196]

If the fuel pump and filter check out it could be water in the fuel tank. A can of seafoam usually does the trick.

 

[mechanized]

Well, I changed the fuel filter just awhile ago. It was the original filter (motorcraft). I drove the truck around and the power is really good, but when I come to a red light and sit there you can hear and feel the engine missing periodically. A couple weeks ago the truck started running rough and the check engine light popped on saying misfire on cylinder #2. That was when I changed the plug and wires, which cleared that up. But since then the engine will still miss and have the problem like I discribed in the first post leading me to believe it may be fuel related. Can a coil pack deteriorate to where it kinda works? Any other ideas?

 

[dynamite196]

I had this same problem with another vehicle, I too thought it was the ignition system at first but low and behold it was water in the fuel tank. Same exact symptoms, rough idle with the occasional stall but power and acceleration weren't noticeable affected. I'd try treating the fuel before you spend time on the ignition.

 

[heaterhotter]

Just out of curiosity and for some opinions.

After how many miles are you supposed to change the fuel filter?
and does anyone recommend a specific brand of filter? i have a 2000 4.0L SOHC.:exp:

----------------
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via FoxyTunes

 

[Cobraguy]

Change your filter AT LEAST every 2 years or 24K. I try and do mine every year or 12K...but only because clogged filters can contribute to fuel pump failure and I HATE changing fuel pumps.

 

[ranger91]

fuel pressure

does anyone know what the actuall fuel pressure should be? i am haveing a similar problem with my 98 5.0

 

[mechanized]

I had this same problem with another vehicle, I too thought it was the ignition system at first but low and behold it was water in the fuel tank. Same exact symptoms, rough idle with the occasional stall but power and acceleration weren't noticeable affected. I'd try treating the fuel before you spend time on the ignition.

I'll give it a try, can't hurt, plus coilpacks at Pep Boys were $98 before tax.

 

[Cobraguy]

does anyone know what the actuall fuel pressure should be? i am haveing a similar problem with my 98 5.0

Off the top of my head...a 5.0 should be between 38 psi and 43 psi.

 

[mechanized]

Well, I bought a can of seafoam and poured the entire contents into my tank along with a full tank of 91 octane. I had my fingers crossed that hopefully that was the issue, but crap it isn't. My truck ran so rough today at one time, I heard a back fire through the intake while getting on the highway and awhile later one out through the exhaust. Not ten minutes later the check engine light popped on. I had to drive from Austin TX. to Wichita KS. today (560 mi.)
I'll run a scanner on "Bucky" (that is what I call the truck now!) tomorrow. I hope to God it is something easy. Like I said before the truck runs smooth while cruising. Weird!

 

[mechanized]

OMG! OK, I have dicked with this truck for two weeks trying to figure this stumbling problem out. Well I kept getting a CEL saying misfire on cylinder 1, 2 and 8. I let the truck run while watching the engine in total darkness in my garage and it was like a lightning storm by those three cylinders. Bolts of light hitting the heads by the plugs. I pull those wires off and those little springs inside the heat shields are burnt like hell. Must be a short here. I pull those springs out and the truck runs as smooth as glass. UNBELIEVABLE! I have been banging my head like crazy on this issue. What the hell are those stupid springs in there for?