I have a cheap Scan tool it is an AUTEL Autolink AL319 I have 3 Codes stored in the Module PO171 System Too lean Bank 1 Sensor 1 , PO174 System Too Lean Bank 2 Sensor 1 , PO1507 Idle Air Control Under Speed Error . Pending Codes shows Also periodically it shows up with a PO335 Crank Shaft Position Sensor Circuit "A" Malfunction , but then the code goes away on it's own for some reason. This is on a 1996 Ford F250 XLT Extended Cab Pickup Truck with a 7.5 Liter V8 460 CI Engine.

Parts I have replaced in order to try to resolve the problem: Idle Air Control Valve is brand new, Checked Connectors, They are fine, O2 Sensors are Brand new, MAF sensor is Brand New, No MAP sensor, No Crank Shaft Position Sensor on this model, (Why is it throwing that code then?, does not make sense) Checked for Vacuum leaks using a Smoke Machine. No leaks found , also Checked for Exhaust leaks, None found, Throttle Position Sensor responds (Not replaced), IAT Corresponds to external air temperature (Sensor not replaced) , ECT Corresponds to engine Coolant temperature (Sensor Not replaced), EGR Vacuum Solenoid is new, Canister Purge Valve is New, Fuel Filter is New, Air Filter is New, Ignition Module is new, Spark Plugs, Plug wires, Distributor Cap, Rotor, all Brand New, Ignition Coil is New, Distributor Internal Pickup Coil is New.

Vehicle Symptoms: Rough Idle in Park, Shaking and horrible Idle in Gear, Engine almost stalls when you put the truck in reverse, Backfiring at throttle and under any stress, Engine Stumble , Slow Acceleration, when attempting to force Acceleration Engine stumbles and Backfires, Unable to accelerate past 45-55 MPH, Engine Stalling when Headlights and heater/AC are on particularly at night, Poor Fuel Mileage, Noxious Exhaust (Smells like Gasoline)

Anyone have any Ideas on this? I am tired of throwing hundreds of dollars at it and coming up empty, I bought the truck from a Wholesaler at an auction for $500 and it did not run at the time, brought out my tool box and diagnosed the problem, fixed it right there on the lot and drove it home., Needed the Distributor pick up Coil to start. It was a Clean Truck 288,000 Miles on it at the time of Purchase, Full Towing Package was included 5th Wheel Hitch, Ball, Receiver, etc. It was a hell of a deal, now I just have to get it running right. In park and Neutral When I rev it up it purrs like a kitten, no shakes no bumps no hiccups, but under load it has tantrums worse than my 2 year old. No Power. Sounded like a timing.issue to me at first, but I have the timing set to Factory specs and it is still not running right. I am a Mechanic with 17 years of Experience and I am left scratching my head here. Sad.. I know..

I am Posting this here because most of my friends are Chevy Nutballs and keep telling me to just give up and drive it off a cliff and buy a Chevy. I say Fords are the Best and I want to prove them wrong! I have owned and daily driven a 1977 Ford Ranchero GT with a 351W 5.8LTR V8 FMX trans Holley H2-2300 350CFM 2 Barrel Carb for 14 years now and have had Zero problems with it other than routine maintenance.
If you guys can help me figure this one out I will be eternally grateful.. I want to keep the F-250,because I really like the way it rides, it is huge compared to the Chero and nice and spacious inside, Tall so I can see pretty well and it really suits me for driving, but it has to be a runner, puller, Hauler, and it has got to run right I need it to pull my 12,000 LB 1978 Twilight Bungalow 5th Wheel 48 Foot Camper It must be up to that task.. We have to fix it guys.. It has to be something simple..

Other information about the pickup truck..
I looked at the Title when I got it back in October and there have been 4 Different owners, Looking at the Mileage on the vehicle it did not change much between owners meaning it has sat. The longest period of time anyone owned it was the original owner who had it for 6 years, no one else has owned it for more than 2 years. The original owner appears to have put 238,000 Miles on it. The second owner only 50,000 miles on it. then between the other 2 owners they only seem to have put 8,000 Miles on it. Must have started developing these problems around the year 2012. That was when the last owner sold it. Interesting.. Oh and the Vin decoder has this information on the vehicle. probably huge and hard to read though. Fuzzy..


Thank you for anything you can say which may help..
~Elijah

 

move to the correct location for your 1996.

 

What were the results of your compression test across all cylinders?

Also the results of your entire fuel injection system diagnosis?

 

Sounds like it had a bad PIP sensor (PO335). Now you need to clear that code after replacing the PIP sensor. It does not have a pick-up coil only a switch.
You may also have low fuel pressure (PO171 & 4).

 

Didn't see it listed, results of fuel pressure testing but possible I missed it?

Lean condition reported, symptoms tend to support that.

Fuel pressure within spec points to the type of vac leak that wouldn't simply result in a high/higher uncontrolled idle speed.
One that would cause a very rough idle/no power say for example, a partially stuck open EGR valve. "Smoke machine" did any check for smoke from the tail pipe?

Lean condition / almost complete lack of power / backfires / reports uncontrollable idle speed / smells like spewing fuel it can't burn from the tail pipe. Yea my first best guess would be egr hung open or supplied with vacuum when it shouldn't be. EVR bypassed and out of the loop or something there not correct.

And while not necessarily effecting the 96 model years yet at this point and especially maybe not the "California" models to start with (regardless, it is 21 years old now so tends to be suspect regardless). If it hasn't been done? it'd probably be worth the few minutes it take, pull its computer checking it for obvious signs of trouble. Budging leaking capacitors, burnt traces etc when inspecting its circuit board.