ethan_

My 2006 5.4 with 260k started running really rough today, with acceleration dropping randomly/ throttle intermittently not working. Thankfully I was close to home so I was (barely) able to make it back into my driveway, but the truck isn't starting right now at all (turns over fine.)

I ran the codes and came back with p0191 and p0133. I did some research and found that these codes correspond to bad o2 sensors (0133) and perhaps a faulty fuel control module (p0191.) My question is where should i go from here, either replace the o2 sensors or try and chase out the p0191 problem? Thanks for the help guys

vintageman

Check your FPDM module on the crossmember. Drop your spare tire and look for it there. Old style is bolted directly to the crossmember and corrodes underneath it real bad to the point of almost falling apart. The new ones have a spacer that lifts it off of the crossmember to help prevent the corrosion.

Tommy J

I would'nt think the 02 sensors bad or not would not allow the truck to start so I would hold off on them but I could be wrong. Could the 0191 be the fuel module under the spare which is a known problem with our trucks. Its on the cross member under the spare and it rots out and causes all kinds of problems. Super easy job after you drop the spare. Of course a new fuel filter would'nt hurt too if you have'nt done it in a while. Theres also a fuel pressure part on fuel rail driver side that could cause problems. At first your symtoms sounded like a bad coil but your codes point elsewhere. I would at least look at the module under the spare and take it off and look at the back to see if its corroded.

STSCDave

I had those codes on my 2007 4.2L. Mine barely made it to the shop, ended up being the fuel pressure sensor under the hood and 02 sensors. The main culprit was the fuel pressure sensor. The diaphragm was stuck so the computer didn't think engine was getting enough fuel. Was blowing black smoke out exhaust.

ethan_

Hey guys, thanks for the advice, just wanted to update the situation and say that I replaced the FPDM and the truck started right up and is running great. The check engine light is still on, but the only code coming up now is the one for the o2 sensors so I'll eventually have to address that problem. Thanks!

Tommy J

Awesome. The 02 sesors arent too bad of a job either. If you have the 5.4 the pass side front one can be a pain so take the tire and splash guard off and you can reach right in and unplug it. Get a cheap o2 tool too. Makes it much easier