Once one thing get's fixed, something else always goes out!!!

[86FordF150]

This is starting to get pretty aggravating. As you all know by now, I have been having non-stop problems almost ever since I have bought and owned the truck. It seems to me like once one thing gets fixed, it only takes several miles before something else happens. And 95 percent of the time, it has been something related to wether the truck runs or not. Right now, it's running, but not very good. And lesson well learned, I don't think the mudding trip helped it any, although it was fun, it wasn't exactly too smart to take a 144 rough thousand miled truck through it especially since it wasn't truly mud, more water than anything else. Now since I got the transmission working fine, now the truck does not want to stay running. It'll start and run in park, but kinda rough, and once in a while i'll here a rattling noise appearing to come from the engine bay. Not often and not very loud but loud enough to hear it. Sometimes it dies when you put it in reverse or drive. Most of the time it will run, but the minute you let off the gas, the rpm's drop drastically and then it sounds like the engine is hardly running and often times when you get to a stop sign, it's only a matter of 2 seconds and the thing dies, then I have to put it in neutral to start and I hate doing that. Here lately I just been working the brake w/ my left foot, keeping a lil bit on the gas with the right and just reving the engine at every stop to keep it running then dropping it down in to drive. What could it be? It acted this way ever since the mud trip but at least it ran a couple hundred miles without crapping out at every stop after that, even though a little rough, now it seems to have just gotten worse!? Electrical issue(s)? Several days ago I had to replace the terminals on the battery cables because they weren't staying tight enough, but problem is, before that the truck was doing the same thing just as bad, only reason I replaced the terminals is because the truck would not start and at least I solved that problem, now what? I might be looking at a trade soon if I can't keep this thing running at least good enough to drive. Oh and by the way, another thing that I can do is let it run in park and if I give it a hefty rev it'll die in park. Don't know what it could be but to me it seems like another fuel problem, but it's not the fuel filter, changed it. The mid frame fuel pump has been replaced. What could it be?

 

[Skandocious]

Sounds like fuel starvation. Clogged injectors? Bad fuel pressure regulator? When's the last time you ran some Seafoam or other fuel treatment through the tank?

 

[1970Custom]

Is it a rough cam style idle? heavy smell of fuel? other little things that you've noticed? that rattle noise IIRC is the engine pinging.

 

[Skandocious]

Got 2 tanks? Does it do it on both?

When's the last time she got a tune-up? Plugs, wires, cap, rotor...

 

[86FordF150]

Is it a rough cam style idle? heavy smell of fuel? other little things that you've noticed? that rattle noise IIRC is the engine pinging.

Sort of yes, and sometimes it doesn't do it but even so the rpm's are still way down after letting off the gas, and heavy smell of gas comes up once in a while yes. I was thinking along the lines of maybe clogged injectors(or maybe they need replaced?) or fuel pressure regulator, but am not sure how to tell, and I am mostly tired of shelling out the money to mechanics. I am somewhat mechanically inclined, but know a lot more about the older styled engines that didn't have quite so much electrical wiring and fuel injection. I would think that if it drove for so long after the mudding trip without dying that it would have done it right afterwards had water or mud gotten in the lines/tank somehow, right, or does it take awhile to really affect it that much? I probably should run a can of heet or sea foam in the tank just to see if it helps any...if not then im stumped. Other little things I noticed is sometimes if I baby it off the line it will sputter just a bit and act a little rough but it hasn't done that too much, maybe once or twice since I noticed the major problem of crapping out at stop signs. The thing that makes me wonder the most is why the RPM's drop so much(I don't have a tach but can tell from the feel and the sound of the engine, trust me, my muffler is rotted out and it's loud enough to tell that the RPM's just drop like crazy) after letting off the gas pedal!?!?

 

[Skandocious]

I'm thinking that the RPMs dropping after throttle is caused by fuel starvation. Have you checked the fuel pressure at the rail? I'd throw a gauge on it and see what you get.

Also, have you tried pulling the codes?

 

[1970Custom]

When my FPR went it didn't kill the motor just made it run like crap, I was at one point getting 110 to a tank.... Also had O2 censor go out once.


Checked timing? how about vacuum leaks? maybe spray some WD40 in the distributor cap.

I agree with Chris though, pull codes or find someone with a diagnostic machine.

 

[Skandocious]

When my FPR went it didn't kill the motor just made it run like crap, I was at one point getting 110 to a tank....

Judging by the way the FPR works, I would assume it could go out either way though... Either starve the engine or flood it. Sounds like yours did the latter.

The fuel pressure regulator (9C968) is attached to the fuel injection supply manifold (9F792) downstream of the fuel injectors (9F593). It regulates the fuel pressure supplied to the fuel injectors. The fuel pressure regulator is a diaphragm-operated relief valve in which one side of the diaphragm senses fuel pressure and the other side is subjected to intake manifold vacuum. The nominal fuel pressure is established by a spring preload applied to the diaphragm. Balancing one side of the diaphragm with manifold pressure maintains a constant fuel pressure drop across the fuel injectors. Fuel in excess of that used by the engine (6007) is bypassed through the fuel pressure regulator and returns to the fuel tank (9002).

 

[mrfixit]

There is a vacuum manifold with several vac hoses coming off of it. Make sure one hasn't popped off, especially the one to the MAP sensor.

 

[1970Custom]

Either starve the engine or flood it.

didn't know that it could starve the engine.

 

[mrfixit]

MOST of the time, the cause of FPR failure is a pinhole/tear in the membrane, flooding the engine. There are certain instances where the valve operates insufficiently, but rare.

 

[1970Custom]

oh, and they're FUN to replace too.

 

[Skandocious]

No kiddin... I've got the instructions on my photobucket if that ends up being the case...

 

[mrfixit]

When Mine went out on my old van, it SERIOUSLY flooded the engine to the point of having to drain the oil and replace it twice, just to be safe.

 

[O'Rattlecan]

my FPR went out and it was flooding it bad a couple years back. Took like 5 minutes to replace, and only cost a few bucks. I was thrilled to see it was the fix.

To the person having the problem, make sure that you get the right FPR when you're at the parts store. There's two kinds. ones with 3 allen screws, and another one with 2.

Ryan