Currently I am having a strange issue with my 1998 Ford F-150 4.6l XLT. The truck currently has roughly 220,000 miles on it and within the last few months I have been getting lean codes left and right. I will get either the P171 or the P174 code. On my most recently visit for its annual service early on in 2023 the mechanic informed me that they tested the battery and the CCA's were low and I might need a new battery. The battery that is currently in the truck was purchased and install in March of 2022. My truck currently has the Viper 4105V that is a 1-way remote start/keyless entry system. The remote start is utilized at least twice a day to start the truck prior to entering it, but the A/C or fan is not placed in the on position when doing so. This last time that I got the code(s) I decided to check all the possible reasons why my truck keeps getting a lean code. I took off, inspected and thoroughly cleaned the throttle body and found no issues. I checked the spring and functionality of the Idle air control valve and there was no issues. I checked the PCV valve and found no issues with it. I checked the ERG valve and there were no issues. I cleaned and inspected the MAF sensor and there was no obvious issues. I checked the air filter and it was clean and free of any debris. I also made sure that the intake hose was properly installed and secured to prevent any kind of leaking. I also checked the PCV and ERG vacuum hoses and they were free of any cracks or leaks. All gaskets were good and free of any breaks or damage when I replaced all the parts that required them. So for the last week I have stopped using the remote start and I have yet to get a lean code. Do you think the remote start may be the reason why I am getting lean codes and that my battery is losing CCA's, and if so what can I do to fix this problem and prevent it from happening in the future.

 

What does freeze frame data show? Might be a clue there. Lean codes often happen on cold engines and/or at idle. Freeze frame should tell you something. If freeze frame is not clear you can also use live data at the same conditions freeze frame showed and learn more.

 

Simply inspecting a MAF is not sufficient. It has to be properly diagnosed.

 

Any recommendations on what to look for in the freeze frame data?

 

Any recommendations on how to properly diag a MAF sensor?

 

I have a '99 4.2l, and I had both the P0171 and P0174 codes (along with a couple of others). I ended up replacing both upstream 02 sensors. I also found a hole in the infamous elbow behind the throttle body, part of the pcv system, that burns a hole in itself and can cause codes, and replaced that as well. On the 4.2l, it's easy to get at. No codes since. It looks like you've done an exhaustive inspection of the pcv system (and I'm not even sure the 4.6l has the same rubber elbow) so you've likely checked this part already but just in case I've attached an image of the elbow. I think it's Dorman part #46022. Best of luck.

 

Engine temperature, RPM, load, among other things. Post up a screen shot if you can.

I'd hose it down with some MAF sensor clean first. Easy to do. It doesn't take much to screw it up. A bug wing will do it. Don't touch anything, just spray.

https://www.crcindustries.com/produc...-11-wt-oz.html

 

A shop has the diagnostic tools to properly test a MAF. Some people try to test the voltage readings which can be sufficient . Here's an example

https://www.youtube.com/watch?time_c...e_path=Mjg2NjY

More thorough testing accounts for elevation / barometric pressure readings.

 

While obviously not that same part, the Tritons have a hose elbow that faces smack dab towards the firewall behind the intake. A pure SOB to get to. It rips eventually and may be OP’s issue.

 

I think this was the best video that helped me figure out how to diag the MAF and rule it out as a possible problem.