Some serious issues here! Please read!

[S10-CRUSHER]

I've got some weird issues with my truck. First, here's the details on the mod's on this truck:

It's a 99, 4.0, Auto, 2WD.

- 5.5" suspension lift
- 3" body lift
- 4:56 rear gears
- Jet Power Control Module
- K&N Intake (tube and filter)
- Dual chamber, 60 Series Flowmaster muffler
- 33 X 12.50 X 16 Mudterrain

Here's the issue(s). The truck has HORRIBLE gas mileage. When I first did the mod's, I did ALL of the mod's at the same time. All the mod details above were done during the same week, all before putting the truck on the road.

Before all of the mods, the truck was BONE STOCK, from the factory. It was getting roughly 15 MPG. After I did the mod's, it was getting roughly 13 MPG. That's of course thanks to the gears, intake, exhaust and Jet PCM. I've done a LOT of maintenance to this truck as well. Such as injectors, fuel pump, fuel pressure regulator, O2 sensors, MAFS, regular oil changes, tune ups, etc.

Today, I calculated that I'm getting only 8 MPG. Just a month ago, I did a motor flush, then an oil change, replaced the fuel filter and cleaned and re-oiled the K&N filter. Just 5 days ago, I did the spark plugs and wires cause the motor fouled 3 plugs.

Here's the kicker: The Check Engine light is on, as well! No matter what I do...no matter how much money I spend on this truck...that CEL STAY'S on! The codes that I pulled were P0172 (System Too Rich 'Bank 1'), P0175 (System Too Rich 'Bank 2'). The truck has had the CEL on for over 2 years now. Even after I replace SEVERAL components, that light is still on and with the same codes EVERY TIME: P0172 and P0175. WHAT THE HELL ELSE COULD BE CAUSING IT TO RUN RICH?!?!

If somebody can give me some tips as to what ELSE I can look at on this truck, I would really appreciate it.

Thank you!

-TNT

 

[RangerSVT]

You need to look at your exhaust system, you mentioned you changed it. What exactly did you change?? Did you delete/modify your cat?? Change the location of your O2 sensors?? Add headers?? FPR, is it an OEM replacement or aftermarket adjustable?? Your JET chip, was it configured for the mods you have, or just a normal tune??
SVT

 

[Big Jim M]

The first place I'd look is that Jet Chip..
Big JIm

 

[Bird]

The first place I'd look is that Jet Chip..
Big JIm

+1

Also, you've probably contaminated the MAF with the oil from the K&N - get some MAF cleaner and get that crud off the MAF sensors.

 

[RangerSVT]

Also, you've probably contaminated the MAF with the oil from the K&N...

While this is probable, this would cause rough idle/throttle response, not neccessarily a rich mixture. Rich/Lean mixtures are caused by injectors, FPR, fuel pumps, O2 sensor readings as well as the ECU sending signals to the injectors, IE chips/programming...I agree with Big Jim, but before pulling the chip, we really need more detailed info on what exactly was done...
SVT

 

[snoman6115]

also as stated in previous cases(sucha s mine) where you are getting both banks lean, CHECK VACCUM LEAKS!!! easiest thing to fix and easiest to overlook by a mile. make sure all your vaccum hoses are good and not cracked. also tighten your upper intake thats where my leak was and after i put in the new gasket from my valve cover kit.

 

[BRUTUS_T_HOG]

don't forget the 2 wire coolant temp sensor. that can EASILY cause this problem.

they cause chevy's to go rich to the point they won't even run all the time

 

[S10-CRUSHER]

Hey RangerSVT,

Thank you for the response. Literally, the only thing that was modified on the exhaust was the muffler itself. All of the cat's are stock and in tack. Not too sure of their CONDITION...but...none-the-less, they're there! Same thing on the O2 sensors. I only replaced them with OEM parts. NO RELOCATION WHAT-SO-EVER! Unfortunately, there are no headers. Just the stock manifolds. The FPR was a direct DEALER (OEM) replacement part. The only place I could get it at was the Ford dealer. Honestly, I'm not too sure of the configuration of the chip. From what I understand, it was set as a normal tune.

Hey Big Jim M,
Thank you for the response. I've been thinking about seeing if Jet can let me ship the chip to them and have them diagnose it. See if it's showing any signs of problems or malfunctioning.

Hey Bird,

Thank you for the response. Honestly, I cleaned the original MAF sensor, I then replaced it as it went bad completely. Since replacing over a year ago, I've done regular cleanings on it just for regular maintenance. It has not helped the operation of this motor.

Hey snoman6115,

Thank you for the response. I've done a thorough check on the leaking of vacuum lines and the intake manifold. HOWEVER, I have NOT replaced the intake gasket yet. Maybe I'll make that a chore.

Thank you all for your responses. I'm gonna look into figuring out this chip and look further into a possible intake leak that I might have overlooked.

SIDE NOTE:
(If any of you, or if you know of anybody that's replaced the belt driven fan with an electric fan, what is the approximate fuel mileage/horsepower gain received?)

-TNT

 

[RangerSVT]

don't forget the 2 wire coolant temp sensor. that can EASILY cause this problem.

they cause chevy's to go rich to the point they won't even run all the time

This is not a Chevy, chevies work with a on/off type system, Fords use a variable voltage system, if it receives no voltage in return, it won't run most of the time...

The FPR was a direct DEALER (OEM) replacement part. The only place I could get it at was the Ford dealer.

Check the vacuum line going to the FPR, it might not be cracked, but make sure it is getting vacuum at the FPR, if no vacuum is present while running, this is your problem. No vacuum= wide open flow (max fuel), full vacuum= restricted flow (minimal fuel) Trace down where the FPR's vacuum line goes, can't remember if it goes to a control solenoid or not...
SVT

 

[Ranger44]

Start with the jet chip as Big Jim said. Remove it, and run it a while, and see if things improve.

Then look for Vacuum leaks. Ford put alot of plastic vacuum lines on there, and they get brittle with age. A good way to check for vacuum leaks is to spray a little carb cleaner along the lines and listen to rpm change. A leak in a vacuum line will draw in the cleaner, and since it acts as a hydrocarbon, will raise the rpm.

Other than that, give us a list of components you've replaced in order to get the CEL off. This can only help us, help you. But alot of things can cause an engine to read lean.

 

[RangerSVT]

Members, I don't mean to sound like a smarta$$ or anything, but all of you are mentioning about a lean mixture problem. He doesn't have a lean problem, he has a rich mixture problem...
SVT

 

[wahl_7s]

you said you replaced the MAF did you replace apples for apples if so i dont think that is your problem with a bad MAF the computer will default lean. my guess would be the 02 sensors right after the manifolds or the programmer

 

[Dweano]

Hey man. You sound kinda like me mods wise...and getting terrible mileage. This might not be much help but change your thermostat. Mine was stuck open and therefore always trying to warm up (aka more fuel)...fixed that and its running better. I also got my tranny fluid changed and that seemed to help a bit too

 

[S10-CRUSHER]

Hey wahl_7s,

Thank you for the response. Even so, the MAF has been replaced. Also, the O2 sensors after the manifolds have been replaced.

Hey Dweano,

Thank you for the response. I honestly don't remember the last time I replaced the thermostat and the tranny fluid could be changed. It's definitely needed. Those might not be bad ideas to tinker with. Thanks Dweano.

-TNT

 

[disciplerocks]

I also nominate the chip. It the only thing you have done that will affect A/F ratio. Keep in mind that even if you get it fixed, running very rich for a long time will ruin a new O2 sensor so you may have to replace them again after its fixed.