My 97 5.4L f150 idles very rough and sometimes dies on me. Also the check engine light came on. I took it to a few different auto zones to see what code it is spitting out and if I remember correctly I think they said it was running lean in bank 1 and another bank but I don't remember which. One of the auto zones said I needed to replace the MAF sensor but the one I went to yesterday said I should just try replacing the fuel filter and run some Lucas fuel injector cleaner in it.

So far I have replaced the fuel filter, replaced the factory air filter with a new K&N, changed the oil/filter, and ran the Lucas additive in my gas and it still idles very rough when stopped whether it is in park, neutral, or just in drive and at a stop light.

Can anyone give me some advice on what to try next? If I have to buy a new MAF sensor then I will but if thats not the problem then I would rather not waste my money. How do you clean the MAF sensor? What is the IAC and what is Seafoam? lol I have read some of the posts about cleaning the throttle body also, will that help?

Thanks!

 

The first place to check and the most common cause is the PCV hose elbow. It usually tears on either end of the hose. Do a search on codes P0171 and P0174 and you will find info and pictures.

 

Ok, I plan to remove and clean the TB, replace the PCV valve (since I believe it is very cheap) & inspect the hose(s), and I guess I better replace the spark plugs too. Or should I wait and see if I need to run Seafoam through it first and replace the plugs afterwards?
Also, should I buy a new IAC or just clean the old one? I read on here someone mentioned cleaning the ISC, what/where exactly is that? Can I re-use all of the old gaskets when putting the TB back together and do I need some silicone seal or anything? Is there a certain torque that I need to tighten the bolts back with?

Thanks a ton for the help...

 

For a proper analysis, post the exact codes here and take what the clowns at the zone tell you with a grain of salt.

 

Ok, I'll go get the codes, thanks again

 

Make sure you look at the scanner and get the numbers

 

Hold off on the seafoam.It you have a bad plug, it won't help at all.

 

Tune UP !!!! Change wires, Plugs as well as check for vacuum leaks. I was having same issues, probably not as bad, but just changed my spark plugs and wires and no more idling issues. Make sure you use good plugs at least double platinum and good wires. Good luck!!!

 

the codes turned out to be the P0171 and P0174 so I pulled off the pcv line in the back and sure enough it had a hole in the elbow. I bought a new line that came with the elbows and pcv valve from the dealer for 39 bucks and it doesn't try to die at idle anymore. I removed the TB yesterday and cleaned it anyway because i figured it needed it. I will be putting it back on and replacing the plugs today so we'll see if it helps even more.

 

It's going to run great after your thru - specially with those new fine wires. - VERY IMPORTANT - You want to pull the boots right from the coils to make sure your springs are connected well to the coil blades. When COP's are removed from the motor, the springs often get pulled off.

Also you have to coat the ENTIRE insides of the boots with dielectric grease - Don't forget that , that's crucial. Be liberal with the grease then slide the boots back over the springs and onto the coil. Don't worry about getting grease on the springs - that's okay.

Some other key components to think about updating in the future to get her running like new - In my case , my 98 runs better than new @ 234,000 miles.

1. Clean the MAF sensor
2. Replace your forward O2 sensors
3. Replace your injectors
4. Replace the coils + connectors/boots.

I have allot miles and over the last couple of years I updated all the above Plus everything your doing currently.

My truck went from a heavy feeling slug to a light feeling quick,responsive and smooth running vehicle. You don't need to modify IMO - just update.

I'm getting 14-16 mpg because I can't keep my foot out of it, but I bet I could get 18 if I could only drive it normally - it's to much damn fun !!

Anyway, new injectors were $60 for all 8 on eBay. You have to look for crate motor take offs and coils can be had for about $100.

Just something to keep in mind. The 97-98 NPI 5.4L motors are very strong runners if kept healthy.

Good Luck.

Helpful Links -

https://www.f150online.com/forums/li...parkplugs.html

http://www.fordf150.net/howto/clean-...low-sensor.php

http://www.fordf150.net/howto/throttlebodyclean.php

http://search.stores.ebay.com/GLOBAL...271212QQsofpZ0

http://www.fordf150.net/howto/

And use my gallery for diagrams and engine/component views. -

https://www.f150online.com/galleries....cfm?gnum=7538

 

can you be a little more specific about pulling the boots from the coils? What do I need to do differently to keep from screwing it up?

 

Yeah I used the hell out of those how to articles and I cleaned the MAF and am about to put the TB back on now. Hey what is that pic of that is taken apart? It looks like a MAF sensor or that little box next to the throttle body or something but its split in half in some of your pics...I printed the spark plug replacement one so I can refer to it outside at my truck. So no anti seize at all?

 

Yea, the boots pull right off the coil. The springs SHOULD stay connected to the coils when you do this. If not , then be glad you preformed this step because a loose spring will cause problems.

If the springs remain in the boots after pulling the boots from the coils - carefully remove the spring from the boot and slide it back on the coil blade.

Grease the boot and then slide it back over the spring and onto the coil.

 

I'm not sure what your referring to ? Post the pic here so that I can explain. Just hit "quote" under the pic if it's in a thread and pull it(copy/paste) and add here.
If it's in a gallery pic, hit "forum code" (right hand side of pic) after you select the pic. Two links appear. Copy and paste the top link into thread (this one). Not sure what you mean , what pic of what ? The TB ? Plenum? Engine? Intake?

No anti seize.

 

https://www.f150online.com/galleries...939-193539.jpg

whats that and what are you doing to it?