about a year ago i started having trouble with my 03 F150 5.4, it wouldnt start. Took it to a mechanic he replaced the fuel filter fuel pump and cleaned the MAF sensor. Year later I start having issues with it again. So far i have replaced the MAF sensor three times (figured it could have been faulty) fuel pump a second time fuel filter twice in the past month, air ambient sensor, air charge sensor, EGR pressure sensor, throttle positioning sensor, spark plug boots, and various cracked hoses. Changed spark plugs about 30K ago put bosch platinum plugs in. Checked for vac leaks cant find any. It is pulling codes P0171 as primary and P0174 and P1131 as secondary codes. Thinking about changing spark plugs. I have run out of options... any suggestions?

 

Bosch plugs are horrible in mod motors. You should change them Motorcraft tune up parts are always best. Po171/174 codes are frequently due to the PCV elbow at the back of the throttle body rotting out. Follow the PCV line to the back of the throttle body remove the elbow and inspect it.

 

Spark plugs are probably not the issue. The lean codes, if bad enough would make for rough/no starts. Describe the no start issue more. Is it turning over fine but wont fire? Is it trying to fire? If you press on the gas pedal will it start? The lean codes typically indicate a major vacuum leak. Wouldnt hurt to clean your IAC either.

 

FYI MAF sensors almost NEVER wear out. They are cleanable. I replaced 1 in a Camaro I had years ago before I knew they could be cleaned. That was 20 years ago and I've never replaced one in any car I've had since.

 

The PCV elbow is fine checked that already. I have motorcraft plugs on hold for me at auto zone thats tomorrows project. Is there a special way to clean my IAC? The starting issue has been ongoing for awhile mostly when it is damp or snowing has it been the worst. Sometimes it wont start other times it turns over couple times then starts other times you have to step on the gas pedal for it to start.

 

what about camshaft position sensor?

 

Pull the IAC and spray it with wd40. Work the plunger around to make sure it is freed up. That may be contributing to your start issue. But the lean codes need addressed also. If the pcv elbow is new, including the rubber fitting in the way back then look elsewhere for your vacuum leak. Stock air filter? Clean your maf sensor again as well. Could be dirty injectors with all the work done recently in the tank that may have kicked up some debris.

 

How should I clean the injectors?

 

Techron is the only fuel system cleaner proven to work.

 

I have a heated pcv valve can I replace it with a regular pcv valve?

 

Where can u get it

 

Techron can be purchased at chevron gas stations or some auto parts stores. What do you mean can you change it to a regular pcv valve? You have the cold climate system. Ive never understood why they wrap it around the pcv valve but as far as changing it to one without the coolant line would require some modifications I would imagine. Like deleting it from the coolant crossover and throttle body.

 

May not be the only thing that will ever work, but with a track record of being the most effective fuel system cleaner made, why would you ever use anything else? Jethat pinned that one!

 

How about the FPDM since you say it is worse when it is damp or snowing? Just a thing to look at and if it has never been replaced wouldn't hurt to do it .

 

The dealership said my truck requires a heated pcv. Runs 75 bucks for the whole assembly. That's y I'm wondering if I can put a regular Pcv in which runs maybe 5 bucks