A couple of days ago I was cruising along and noticed my Check Engine light was on. The truck seemed to be running fine, but I pulled over and turned it off anyway. Checked fluids etc., everything was good, so I restarted and the light was off. I thought maybe it had just gotten "stuck" or something. A few hours later I hopped into old faithful again and the dang light was back!! So I ran it down to the auto parts store and had them run the codes. It came up with a code 41 No Exhaust Gas Oxygen switching detected-always indicating lean...and a code 67 A/C on during KOEO or nuetral drive switch open bla bla bla.. (My AC doesn't even work in the truck so it couldn't have been ON). I guess I am just being thick headed here
but can any of you tell me in plain English what my problem is with the codes of 41 and 67??? And what do I need to replace to get the silly light to go away! Thanks in advance.

 

Check the wiring to the O2 sensor - that code will come up if it is unplugged. If your truck is a 4.9L with a stick shift, you have to push the clutch pedal down when you run the test to keep 67 from coming up.

 

My 89 460 does the 41 code if left idling for to long. Defect in the computer. I just ignore dosent hurt any thing. Never heard of this in a 1/2 ton before. EPN is right check the O2 sensor it may need replaced or cleaned. If it has been a while I would just replace any way. It would fall into the tune up catagory on an EFI.

 

hey guys im lookin at this 1990 f 150 full bed looks like a realy nicely taken care of truck has a new tranny new clutch new hubs new tired straigh body its an inline 6 301 i just wanted to no whats the down side to the inline 6 and whats good about the inline 6

 

My truck has a 302 and it's an automatic. Thanks for the suggestions on the O2 sensor, I'll look into that. Do you know about how much replacing that will cost? I have heard that sensors are pretty high sometimes.

 

Best I remember, my O2 sensor cost around 50 bucks. Code 67 could indicate a problem with the gear shift position sensor (MLPS). Try the test in neutral and see if that makes a difference.

 

Thanks again for the help. I seem to have developed a new problem now, unless they are related?? Truck runs smooth when accelerating, but when I lift my foot off the peddle the darn thing will buck or jerk. Sometimes it isn't very noticable, and other times it is a very strong buck that makes a clunking sound. Can anyone give me any ideas on what this might be and how expensive it is to fix?

Again, I have a 90 F150 with a 302. Thanks again.

 

Maybe start with checking out the MLPS for the transmission. If the computer is not sensing the right gear lever position, it could be running things differently.

 

I've got the same problem on a 95 F150 4X4 with 302, except mine will do it sometime accelerating. I really notice it when I shift into 2nd sometimes it will jerk pretty hard and is terribly annoying and probably not good for the rearend. If you find out what fixes this let me know, and I'll do the same for you. Mine came up with a Throttle Position Sensor code so I am going to look into that.
Tom

 

I'll do that, Thanks. A friend of mine mentioned that I should check the U-joints out too.

 

trucknfool - My problem was my throttle position sensor I think. It was giving me the code for that so I swapped that, but I also put on new battery cables as the old ones were cruddy as well as a new rotor - they guy I bought it from had already purchased but just hadn't put on. It was one of the three things, but I'm pretty sure it was theTPS as the code is now gone. Maybe that computer really does work sometimes.

 

I am having the same problem, but before the jerking in the acceleration i have a loud shudder at around 35-40mph is when it happens. It sounds like if the U-Joints where going out. Anybody having answers. I would appreciate the help.

 

check the codes per instructions on the www.fordfuelinjection.com site and go from there. That worked for me, anyway.