So, a few days ago my truck (97, 5.4, 8ft, 180K mi.) threw out rich codes for both sides. She was driving fine yesterday (I drove it 45 miles for the first time in 3 months), but this morning it started bucking like I had a misfire. It gets REALLY bad if I try to give it any throttle, so when it happened I pretty much had to idle her home, and couldn't get over 30mph unless I was going down hill. It's not like a regular misfire feels (one of my new coil packs ended up being defective two weeks ago, so I know that feeling). It's like she's going to explode or something.


This is the work I've done over the last few months:
~Coil Packs
~Plugs were done last year
~Injectors (2lbs higher injection, but dealer said computer should be able to work that out)
~Intake manifold gaskets
~Throttle body gaskets
~Installed headers and replaced gaskets

The temperature guage doesn't work the dash. I tried replacing the sensor because it was stuck in the red zone, and now it won't move up. I know this sensor has something to do with timing and fuel mix.
Other than that (and the 4x4 not working), she's in decent health.

Now, I've never replaced the cats on her (again she has 180k mi.). I'm leaning toward getting univerals. If I'm going to have that done, I might as well get true dual...

So, anyone out there experience this before? I know cats can cause a plethora of insane symptoms (engine stall, false transmission symptoms, false fuel pump symptoms, etc.) I've never had two cars with clogged cats have the same symptoms before, so I know it's tricky.
I have not noticed "that smell," nor did I remember to see if they were red last I drove it.

Thank you for any and all advice! Let me know if you need more information.

 

what kind of plugs did you put in?

 

I'm not exactly sure. It may have been two years ago that the plugs were done, as it was before I got the truck from my dad. I remember him complaining about them being expensive, though. I also remember talking to him about gapping them right, because he bought a book for the truck. As far as spark plug type, I don't know for sure. :/

 

well MotorCraft plugs are really the only kind that work well with these motors. other plugs will not last as long and my come apart inside the motor. i would pull one plug to see if it looks ok and check the gap, but if its not a MC plug i'd pull all 8 and replace them because it does sound like a misfire IMO.

 

Check your fuel pressure regulator. Too rich may be a symptom the regulator is not keeping the pressure at 39 psi. If it's been running rich for a while, it may have damaged the cats. If the regulator is bad, it would be a good idea to change your plugs because of fuel in the crankcase.

 

Pull the vac hose on the regulator and see if theres any gas present in the vac lines. You should also check the EGR system also.. Make sure everything is open and running smoothly. Have you tried running sea foam or some kinda injector cleaner?

Check your battery too! A sure sign of a battery about to crap out on you would be your truck running like crap.

 

Had an explorer act like that once, was a bad Mass airflow sensor.

 

I was just going to say that. I would pull the plugs and check them out.

 

Spray the MAF sensor with a non residual contact, tuner or electronics spray. That is where I would start. If you have a scan tool reset the MIL with out disconnecting the battery.

Edit: Don't touch the wire in the MAF sensor

 

Thanks, guys. When I had the motor apart I cleaned the MAF, and I will definately get injector cleaner when I can get it to move again. My dad had car that we thought had a bad MAF, and after the expensive replacement of it and the problem not going away, we whacked the cats and it ran fine.
I know I definately need to replace a few vaccum lines, and I'm going to check the EGR tomorrow. I was also thinking it might be the vaccuum regulator, since the roughness has been off-and-on. I'll grab a pressure guage from a friend for the fuel.
The cats are getting changed no matter what, I think...180k is too long to have original cats, especially since I know the intake manifold was leaking antifreeze into them for years... :/
I was really hoping it was just plugs, but it doesn't feel like a plug/coil issue because last time I had a code pop up immediately on the first misfire, and it felt different in the motor.
So I'm going to go through all this great advice one at a time, and get back next week to let you know if I need more help, or let you know what fixed it.
Thanks again! And please feel free to post anything else you can think of!

<3

 

Oh, and Tumba, I do have a scan tool, and I'll be sure to do that. Best investment EVER. ^_^

 

I think it could be the calibration required after moving the throttle position sensor or butterfly.

 

So, I'm replacing the EGR system today. A bunch of carbon came out of a few of the vacuum lines. :/ I'm also going to be having the catalytic converter's changed, because after inspection by two exhaust shops, both said that the drivers side is nearly totally blocked off in the pre-cats. Since neither carry universals, I have to go out and buy my own, and then one of them will do it. Something about how Fords are too sensitive...but I've had 2 Fords with 49-state universals, and had no problems with either. Thank you everyone so much for the ideas! You've been more help than I can express!!!