Posted this in the big block section, but got no responses, so here is to hoping you guys are able to help...

This concerns the pick-up in my sig. I had read a few threads with similar problems, but none of the OPs reported back if the problem was fixed! Grr.

The truck has occasionally been acting odd whilst driving down the road. Most of the time it has been running ok, but sometimes I cannot get my RPMs over 2k in4th or 5th gear. It will cruise at 2k RPMs for a while, then go back to normal with normal acceleration.

Then today, under acceleration, the truck would lose power, the CEL would flash OR stay on for a while, and stumble and jerk a bit. Took it to a shop for the code reader. Pulled 171, 172, and 181. Two mechanics from two different shops said to replace O2 sensor, which I did.

At the same time, I replaced the plugs, wires (yes, I did one plug and wire at a time, so no, I did not cross a wire somewhere), distributor cap and rotor, air filter, and crankcase air filter. The battery was completely unhooked during all of this. Then I let the truck idle for about 15 minutes after I hooked everything back up.

Now, the truck idles and revs fine, and under VERY light acceleration, I can get up to 70mph fine, but if I try more than a tiny bit of acceleration, it stumbles and jerks badly, and the CEL comes on. I checked for arcing at the distributor in the dark and that was good-to-go.

What do you guys think? I plan to replace the PCV valve tomorrow, but other than that I am pretty much at a loss.

Thanks

 

Update: Truck barely got me to town today. It would cut out and die no matter if idling, revving, or accelerating. And it was extremely difficult to start again. Cut out the cat this morning, thinking it may have been clogged. There was no change.

Changed out the fuel filter. Man, you should have seen the black runout from the old filter. I suspect it was the factory filter, yikes!

Now the truck idles, albeit not smoothly. It idles fine for a few seconds, then starts to die out, then idles back up to normal. It drives better, but still quite poorly. I could get home, probably.... I think.

I think the gunk in the lines from the old filter just needs to get out of the system, right?

 

You may have low fuel pressure. If you have two gas tanks,switch to other tank. If that doesn't help then check the pressure at the fuel rail on the left side of engine when looking from the front. The valve looks like on on a tire. I don't know the proper pressure, but it should be over 30. Problem could be a bad fuel pressure regulator.

 

I do have dual tanks, however I cannot use one of them. I will go get a fuel pressure gauge when I get done eating my lunch. Thanks.

 

I would say it sounds like you may have a clogged injector(s) due to the amount of debris in the filter. It also wouldn't hurt to have the ignition control module checked at an auto parts store. Easy to do a free at most places.

 

What did the codes 171, 172 and 181 refer to?

 

Nevermind, I figured it out. You're running lean, so yes look into fuel pressure first as others stated. I'm not familiar with that motor...where is your fuel pump?

http://www.troublecodes.net/Ford/

 

what do you mean get to town? you live in scottsdale right?

 

Did you finish your lunch and get a fuel pressure reading?

I would also check the TPS output throwout the throttle throw. Make sure it goes from .0-.4ish up to 5.0ish volts smoothly.

And make sure the hose form the manifold to the MAP sensors is good as well.

 

I am currently working in the oil fields of North Dakota. Parts and tools are hard to come by in these small towns. There is no fuel pressure gauge available at the NAPA here.

Fuel pumps are located in the tanks.

Yes, I have finished my lunch and am back to the truck. Thank goodness for cell phones with mobile hot spot for my lap top.

We put a tire pressure gauge on the fuel rail and am reading 26 pounds at idle. The pressure drops as it idles until it dies. Fuel pump or pickup, I am guessing.

Also, I replaced the tee coming out of the PCV valve, which is on order. I will upload a picture of it later. It was junked.

 

Does it act up on both tanks? If it doesn't your pumps and pickups are good. If it only acts up on one tank than you know where the problem is.

I would start with replacing the fuel filter on the frame.

 

Replaced the filter earlier. Thought I mentioned that.

Cant use the rear tank in the first place. But, tried to switch tanks and it did not run any differently.

NAPA closes in about 5 minutes, so I bought a fuel pump just in case. They will not be open tomorrow. If I can get it home, I can pull it in a garage which I can heat up a bit.

Does anyone know if I have to drop the front tank completely? It looks like I might be able to tilt it and get the pump out.

 

Pretty sure you have to drop the tank.

 

Going to TRY to get home now. It is about 13 miles or so. yay...

 

Heck, didn't even get two blocks. I am in the parking lot for the county courthouse, haha. My only possible ride I can call is not answering the phone either.. joy!