Hey guys I'm new to this site. I recently bought a 2005 F-150 from a guy off of Facebook Marketplace. The truck drove well while test driving it. I had planned on getting a tune up and oil change on it just because I didn't know when the last time it had been done. A couple of days ago I noticed the check engine light was on and when you floor the gas peddle it would be very hesitant to go and after a couple of seconds it would start going. I took it in to a local mechanic and they thought the wrong spark plugs were in it until they called me and asked if the motor had been replaced and I remembered the guy I bought it from telling me it was a newer motor. The mechanic was able to pin point that it was a 2008-2010 motor and stated that after changing the spark plugs, oil and filter, filter and fuel filter it was still showing on the computer reader reading "lean." He said that he wouldn't be able to do anything with the programming of it unless I could get the VIN# for the newer motor that was put in a little while back. Well of course I couldn't get the VIN# so I'm back to square one. Not that the truck didn't need all of the necessary changes i listed prior. Has anyone ever heard of this issue and if so could you please enlighten me on what you think I should do about it. BTW, the truck will get me from point A to B but it would be nice to get the problem fixed. Any help would be appreciated. Thanks

 

I would start with the MAF sensor, clean it with MAF cleaner and let it sit for 30 minutes to dry.
ps. I will tag a moderator to move this to the correct forum

 

Moved you here, may have to go engine specific if no one has an answer.

 

A 2008 up has different heads .They use very different plugs . They do not use the long snout plugs I can't speak of other changes ,can't think of why there could be more differences . The engine number should pin some things down . Of course you have vcts that require different small seals and must pull valve covers to change vcts .

 

You're going to have to post what ever new codes are here.

 

Thanks for the help. I will pass this on to my mechanic.

 

Thank you, I appreciate it.

 

The codes that kept coming up were PO171, PO174, and they state that it's too lean and list B1 & B2. Not sure if the first two are O's or zeroes beside the P 171 & 174.

 

Yes, I saw the plugs that should be in a 2005 as opposed to what is actually in there now and they are two different looking spark plugs. One has more thread on it for sure.

 

Well if your plugs don't have the long snout on them then the heads are late 07 -08, that is a good thing .
Your codes are lean both banks which indicates a vac leak . It should be smoke tested . you can build one off youtube . you just connect it to your brake booster hose put a couple of pounds of air to your can . I made mine out of a new paint can ,fittings in lid , Shrader valve with a locked on air hose from small compressor ,big tygon hose fitting thru lid to brake booster hose. If smoke comes out throttle body throat then put rubber glove over it . Cotton rag with mineral oil light in can watch smoke travel up tygon clear hose . Smoke test at a dealer usually expensive .
There should be no programming issues -no pcm problem . Clean maf and throttle body with proper cleaner. You may need to see if o2's are working switching etc . O2's and maf determine fuel ratio but a vacuum leak will mess them up they can't see that air coming in and adjust for it . Check purge valve on firewall can't be blown thru for a test . You can smoke test the brake booster sometimes they rust out .