I am new to this site, but have been a Ford truck lover for 30 years. I have a 97 F-150 4x4 with the 5.4 auto over drive tranny.
My problem has been intermitten. My check engine light was on when I bought this truck. I test drove it and everything seemed good, so I didn't worry about the light. about 2 months ago the truck started giving a problem . It will seem to be running fine, then out of the blue it will not accelerate at all. I first thought that the tranny was not shifting out of overdrive so, I tried to do it with the button. but the button didn't work. The off light stayed off. I shifted to neutral and pushed the foot feed and the engine would accelerate but with hesitation. I had to pull off the side of the road. I kept it running in park and tried to get the overdrive to turn off. It didn't appear that the button was working at all. Next, I turned the key off and restarted the engine. After the restart everything worked. I went on to where I was going with no problem. I had a mechanic read the codes on the truck and he got a bank 2 sensor 1 oxogen sensor code.
I had the sensor replaced and it put the check engine light out for about 1 day then it came back on . Next I had the mechanic put the sensor that he replaced on the other side. This put the light out(after reseting the computer). Now, the check engine light comes on about once every 100 miles or so and when it comes on the truck will not accelerate and the overdrive button will not work. but all I have to do is turn the ignition key off and start it right back up and the check engine light is off and everything appears to work right.
If anybody has had a similar problem I would love to hear how it was fixed.

 

well, you are best to get the codes read. Autozone will do it for free. These trucks tell you what is wrong with them through the codes so that you can make an educated decision instead of guessing (for the most part)

 

I checked with Autozone and they said they can't read code unless the check engine light is on. Is it normal to not be able to read code if check engine light is not on?

 

If the check engine light was on there should be a code stored in the PCM's memory. They should be able to retrieve that.
After you've restarted the truck does the OD switch light work?
Has anyone tried cleaning the MAF sensor?

 

After I restart the truck the check engine light is off and the over drive switch and light does work. I have not had the MAF sensor cleaned. Do you think that might be the problem?
I will check with Autozone and see if they will hook up their code reader with my light out.
All advice is appreciated.

 

No I dont think the MAF will cause your problems. Youre going to have to get it scanned for memory codes so you have a place to start. If Autozone cant do it for you I would take it to your dealer.

 

Racerguy, I finally was off work when Autozone was open. I had them hook up their code scanner. It showed no codes. My check engine light was not on at the time. The Autozone employee that performed the test said that their scanner would not retrieve codes that were in memory. Do you think that a dealer is my only choice to get codes from memory? That is what Autozone seemed to think. Glad I asked them to read first though, because I almost paid 150.00 for a code scanner at Autozone just like the one that they used.
Thanks

 

I wonder what kind of scanner it is that cant retrieve memory codes?
Sounds like something that sure isnt worth having.
If you dont want to go to a dealer you can se eif you can find someone with a more "professional" type scanner such a s Snap-On. Any good scanner should be able to read memory codes.

 

I had a similar problem with my wife’s 2001 Expedition. She was driving back to work when she started to feel the Expedition loosing power. The RPM’s would raise and the speedo would increase, but the butt of the seat feel was not there. The O/D light started to flash and I took it back to the dealer.

The Expedition would work fine for the first thirty minutes and then the slipping would get worse and worse until I would have to use 1st and 2nd to get the Expedition going. The service writer told me to get into the dealership ASAP. I took it in and they had to replace almost the whole transmission to the tune of $2,300 (warranted).

When I got it back the problem started to happen again and they were stating that it was because it is hot. (NO, really this is Arizona in the summer!) I took it back and they had to download a new summer “hot” program for the transmission.

Got it back and it was still running rough, so I took the negative connection off to reset the computer and that fixed it up.

 

Has anyone ever heard of an on board computer going out that would reset when vehicle engine was turned off then restarted?
I have been hooked up to a code reader 3 different times and it looks like the codes are not storing. This was what my mechanic and a Ford tech decided was my problem. . Any of you Ford techs ever heard of this. I am waiting for a salvage yard computer to try.

 

yes they do go bad..why wait for a salvage yard computer..i can get most ecm's for around 100.00 price a new one also im not sure, but your prom may be bad..not the whole computer. See if theres an updated prom..

 

I got my salvage yard computer installed and everything seems to be okay for now. I have another question along the same line.
when changing computer we found a component that plugged on to the end opposite of the wiring harness. It says Street and Performance electronics. It had come unplugged and was under the carpet edge . It is about 3/8 ths of an inch thick 3 inches long and as wide as the computer is thick.
any input would be helpful. I didn't plug this component on the replacement computer and don't know if I should or not.
Thanks

 

It could be either a transmission modifier to change shift points or it could be an ecm modifier changing shift,fuel etc.. id trace it back and see what the plug is attached too..there just may be a part number and manufacturer name somewhere on it ..

 

Overdrive doesnt kick in until after about 30 mph or more

 

I think there may be a missunderstanding on the component that I found near my computer. there was a place where the computer board was visible directly on the computer on the end opposite of where the wiring harness plugs in. the component is female and there is a computer board plugs directly into the component.
MUDDA, I didn't find any part numbers on it anywhere, but hoped that where it plugged on the computer would narrow it down as to what it's function is.
Thanks