2001 Ford F150 - 4.2L VIN 2 Lean

[MarionB2BAuto]

I am wanting to put this out there before I get too far in depth. I have done some general inspections, but nothing is obvious.

Vehicle is a 2001 Ford F150, with the 4.2L V8 (Vin 2) engine. He has had a history of both banks lean and has been taking it back to the same dealership for the past year. They have replaced the intake manifold, and have replaced the manifold gaskets (upper and lower) two more times. He is still getting both fuel trim lean codes. LTFT were around 14% bank 1, and 18% bank 2. I have tried propane tests both hot and cold, and cannot see a difference. Any help would be greatly appreciated. I am not hugely familiar with Fords. My 20+ years have been with GM, with the occasional used car or exotic that would come into the shops. Now that I have my own, I am working at learning the different ones. So please, any help would be greatly appreciated! Thank you all in advance!

[brianp87]

What is the fuel pressure reading? These have a revised parts for manifold. Its also common to only leak cold. tsb 05-22-6

[MarionB2BAuto]

They installed the revised manifold from what I have been told. As for the fuel pressure, I will have to look at the diagnostic sheet. Will post that soon.

[liljoe]

I would check fuel quality also, we have some stations around here that seem to have too much ethanol in the gas and I have had fuel trim problems from some cars and trucks that use it, esp if they have any carbon build up at all. That is one of the top things I look at for fuel trim issues around here.

[steven kiser]

A MAF will do this ad i believe there was an updated intake for these and if the install kit wasn't used it would create an internal intake leak.

[liljoe]

A MAF will do this ad i believe there was an updated intake for these and if the install kit wasn't used it would create an internal intake leak.

MAF is on the real short list too. Just go WOT with scanner hooked up and look at grams per second when the engine is at the upper RPM range, look at RPM, MAF, and TPS to make sure you are at WOT. Formula is RPM in thousands ( 6,000 RPM would be 6 ) times engine size in liters, times eight. For a 4 liter at 5,000RPM it would read like this: 4*5*8=160 gps.

[MarionB2BAuto]

Hey all. Thanks for the good input all! I will be checking all of this.

[liljoe]

I am sure you will get it figured out as long as you do not overheat your self. It sure is hot in the Heart of Dixie........

[MarionB2BAuto]

MAF is right on the money. at 4000 rpm, I need 134 g/s, which converts to .297 pounds/s (my scanner was set to pps) and I was getting .3. I am wanting to check fuel pressure, but according to Mitchell it shows that the test port is on the fuel rail, but I have looked and can't find it? Any ideas?

[ricmorin]

Hmmm. Should be on the left side. I think it sits sideways instead of straight up?

[steven kiser]

If it's not there lets step out of the box here. I've worked on a few Ford trucks that needed injectors and for some reason i've found the rail rusty or had rust in it. Scored them from Jeggs as opposed to OEM for much less money and availability. Now if the rail has been replaced look into the injectors. I had a truck in (GM) and it drove me a bit crazy. Nothing was dead nuts wrong but something was up. The owner had installed incorrect injectors because he never read the fine print and saw the pcm needed to be reworked. After market parts are made to look just like OEM and it took a magnifying glass for me to see the #'s weren't manufacturers.

I replaced a few of these manifolds with the updated ones and along the line Ford decided to sell the install kit separate from the manifold. I was lucky because the first run had the new bolts in the box so when they stopped i knew something was up. The old original bolts would seal temporarily but not tight enough to last. Tightening them only snapped them because the bottomed out.

[MarionB2BAuto]

Obviously I am going by what the customer has told me, and the receipts in the glove box, but so far all work has been done at the dealer. He has had it in 4 times over the past 14 months with both banks lean. Every time they have either replaced the manifold (TSB) or replaced the gaskets. A propane leak test shows no signs of leaking around the manifold area, or elsewhere for that matter. I am having to get an adapter for the fuel pressure gauge so that I can get it in-line at the fuel rail since I have been unable to locate a port. I am suspecting, as has been mentioned, a weak fuel pump.

[jbadenoch]

freeze frame info can sure help. I've had quite a few fords with 174 and171 where the maf tested good but was not. Intermittent issues i guess. Just 3 cents worth. Let us know what ya find. Good luck and stay cool, 105 deg in sc

[MarionB2BAuto]

Fuel system test this afternoon shows KOER pressure at 32 PSI. Spec says 28-45. So I am within spec there. MAF tests good. Can't find any vac leaks. This is one confusing truck. All data shows things are fine, but the lean condition code still exists for both banks.

I know it is POSSIBLE, but never seen it before, could BOTH precat oxygen sensors have gone bad? they switch like they should in the data list.

[liljoe]

Did you test for alcohol in the fuel?

[MarionB2BAuto]

I will honestly say that no, I have not checked for alcohol. I assumed that fuel content would not be an issue since he has had this problem for over a full year. He puts a decent amount of driving on this, including out of town, so he is not refueling at the same station either. Good thought tho! Thanks.

[steven kiser]

Did you test for alcohol in the fuel?

Talk about a waste of booze. Sounds like the jet fuel uncle jesse makes in the hills. I remember one race when Bo used it and won.

A lean code akin to this was solved one time by using a new maf as opposed to cleaning the one in it or using a reman. Even the ones from the dealer can be reman and you may assume they are new.

[MarionB2BAuto]

For lack of any other signs of failure, I am going to replace the MAF sensor and see what we get from there.

[jbadenoch]

For lack of any other signs of failure, I am going to replace the MAF sensor and see what we get from there.

Been waiting for that one. Let me know

[MarionB2BAuto]

My apologies for such a long delay. Replaced MAF sensor and customer has driven truck for several weeks now. no reoccurance of codes, and he is thrilled that it is fixed. thank you for your help!