Hi, i'm new here, so bear with me.I have a 1997 F-150, the check engine light came on, I went to an auto parts store and had them hook up the OBD. It came up with a code, 56, the guy said it was an "input speed circut problem". He went on to list 3 things it could be, Mass air flow sensor, Manifold air pressure sensor, or the Throttle position sensor.
This leaves me with 3 problems. One, code 56 doesn't jive with my code list, two, how do I tell which of the three sensors to replace?Three, do I have to shell out the $$ for all three parts?

 

sounds like you need to get the code read at a place that knows what thay are doing,or a scanner that knows what its doing.i agree that the code dont sound right.if it is a speed code,it could be missing vss signal,engine overspeed ,or vehicle over speed.

 

Thanks l-m tech, where's a good place to go to get a reliable code read? I'm on a 'tight' budget. I really try to avoid the local dealership because of a bad history with their service dept. Also, does anyone know where the 'Manifold Air Pressure Sensor" is located, my Haynes library manual makes no reference to it? Is it called something else?

 

Welcome to the forum.

You have an AutoZone near by? They will scan it for free. Write down the codes and post them here. We can help.

 

I got a code that jives w/ my code index....P0301...Cylinder #1 misfire, please tell me its just a fouled plug?! If not, what else might it be, bad plug wire? HELP...Thanks, John

 

I have engine problems of my own. I have an 97 F150 with little over 100,000 miles that shows that the oil is going low while sitting at a light. Had it checked out by a mechanic. They can not find anything wrong. any suggestions? Nancy

 

If you have a 5.4 you will need a coil & a new plug to fix your truck if it has a cylinder missfire. I've replaced 2 of mine. I think the 97 4.6 still has plug wires.

 

My truck started to misfire about a month after I had it tuned up. It turned out that it needed new spark plug wires. The check engine light had come on, and I had it checked out and serviced. I was surprised that they didn't tell me to replace them when I had the tune up done. Nancy

 

Had the very same code on 97 150 w/135,000 miles. Plug wire was bad. Went to local dealer, bought cylinder one wire for about $10, put on and runs like normal.

 

Any suggestions on why my oil gauge goes to 0 while idling at a light and hauling a trailer? I had it checked out by a mechanic who can not find anything wrong with the vehicle. Of course he doesn't have a little horse trailer behind it. My truck is a F 150 with a 6 cyclinder automatic engine with 113000 miles on it. I bought a new oil pressure sensor, but can not get the old one off. Does it require a special wrench? If we get a big enough deep socket to fit the old sensor, the wrench can not fit in the space. Nancy