Hi all! Been perusing these pages for several weeks but just signed up as a new member. Heres my brief story:

I just bought my first-ever Ford truck about a month ago, a 1997 F350 crew cab 2wd long bed with a 460. I've been a faithful GM owner for 23 years, only having owned one Ford product previously-- a 1994 Escort wagon. I decided to switch to Ford because of all the BS going on with the government and GM, I refuse to continue to buy/own anything having ties to Obama and his crooked socialist administration. Ford is still hanging in there and standing on their own feet, something that goes a LONG WAY with me.

Anyhow, I've owned this Ford for about a month now. It runs great, everything works, and its a good looking truck (the last year of the really cool Ford truck body style, IMO). It has plenty of grunt, pulls my 19' camp trailer and all our gear through the hills with MUCH less effort than my 1997 Silverado 5.7L did-- no comparison. And I can't see that the fuel economy is a whole lot different either, my 5.7L getting maybe a mile or two per gallon better but having to work a heck of alot harder.

The guy I bought the truck from told me that the truck runs fine on 87 octane fuel but that if I plan to tow a load in the hills, I should fill up with at least 89 to avoid pinging. Our first trip I did just that, used 89 and everything was great. On our second trip I cheaped out and filled up with Arco 87. The pinging was very noticable, and when almost to our campground and after a long pull up a 6% grade, the check engine light came on. It was not overheating or any other issue I could observe with the gauges, so I figured the knock sensor had probably tripped the light because of the crappy gas. The light reset itself after a couple of days. On our third trip just this past weekend, I again used 89 and all was well until we got back into town. We stopped at the Burger King, and when merging back on the highway (hard accelleration), the light came on again even though I could not hear any noticable pinging. Ok, so now I'm a bit concerned.

I know I will probably need to invest in one of those OBDII code readers, but I was hoping maybe someone here with more experience than myself could possibly point me in the right direction. The light comes on only immediately following a hard climb or on-ramp-style accelleration, so I'm assuming it might have something to do with the emissions system. The truck passed smog with flying colors just 2 months ago, I have the fresh cert right here. Any advice? Reccommendations? What is most likely to be causing this light to come on under these circumstances? Thanks for any help!

 

well there is a lot of things that it could be. but if you can get it scaned that will eliminate the guessing and save you some time. there are a few auto part stores that will scan it for you free like autozone advance auto. not sure if you have any of thoes in your area just a suggestion. your main concern should the pinging (detonation) that will damage your engine. you need to make sure your ignition timing is correct and all sensors are working properly. a bad sensor can mess with ignition timing air fuel ratio economy ect. i would get it scanned probley something simple . take a look at vacuum lines visible wire problems make sure everything is pluged in

 

I went over to a friend's house this afternoon, he has a code reader. The trouble code is P1151. Looking up some info on the internet, it appears an oxygen sensor may need to be replaced? P1151 indicates a lean condition, among other things, but after researching some of the symptoms of the other possible issues, my truck does not seem to be experiencing any of those. Whats left is either a bad connection, moisture in a connection, a bad PCM, or a bad O2 sensor. Since the code only appears on hard acceleration or a tough pull, I'm assuming its not one of the other issues (or it would happen all/any of the time and not only under very specific circumstances).

Does my thinking seem reasonable?

 

Also, if it were a lean condition due to a vaccume leak, or a MAF issue, or something else, wouldn't both pre-cat sensors be reading the lean condition on both banks? The P1151 code is just bank #2, or driver's side. This also leads me to believe its a faulty sensor, likely giving up after 120,000+ miles. Probably wise to check for vaccume leaks and the MAF while I'm at it, but I'll replace both pre-cat sensors. If one is going south, the other is probably nearing the end as well.

 

Gee whiz guys, thanks for all the help.

 

you got it figured out?