My 1997 F150 5.4 check engine light came and>
While idling or in Park the RPMs will drop below 500, then the RPMs will jump to about 1100 and then back down constantly,my gas mileage is terrible. On my way to work today the check engine light started flashing (continuously), and when I would accelerate it felt like I was on a gravel road until I reached the speed-limit then it seamed fine, excluding the flashing CE light??? Many Thanks in advance for any help or advice.

 

Sounds like might be a coil pack. That vibration you experience is probably the roughness of running on only 7 cylinders.

Bring it into the shop to have the computer tell ya which cylinder it is. If it's cylinder #4, have them check the coolant plumbing near-by and tighten any loos fittings.

Please let me know if this was it. I just fixed mine for the same reason. BTW, cylinder #4 is up and under the damn cowl.

 

I have a 97 F150, 4.2 liter, 2wd....It too has the same symptoms....Almost no acceleration and the check enginge light flashing....When you step on the gas it just sputters and sputters until you let off....I suppose I will have Ford check the coil pack like the guy above mentioned.....

 

"My 1997 F150 5.4 check engine light came and>
While idling or in Park the RPMs will drop below 500, then the RPMs will jump to about 1100 and then back down constantly,my gas mileage is terrible."

ANSWER: The above problem was fixed by replacing the EGR valve.


The check engine light started flashing (continuously), and when I would accelerate it felt like I was on a gravel road until I reached the speed-limit then it seamed fine, excluding the flashing CE light??? Many Thanks in advance for any help or advice.

ANSWER: The above problem still exist after the EGR valve was replaced. Guess what I took it to AutoZone and found a misfire on cylinder # 4. I'm presently going through the Haynes manual to find out how to change / test it.

 

Had the same problem on my 97 250LD. Autozone gave me the misfire code for cylinder #5 (305). Bought a new coil for about $50 bucks and changed it in about 5 minutes. If it was one of the back four coils, I would have taken it to a pro, but #5 is right in the front so it was an easy fix! Kudos to Autozone!!!:-)

 

 

i got a 97 f150 its got the 5.4l engine in it the truck reves real high before shifting runs little rough in park at idle drops way down to 500rpms first and second gear are fine but third gear reves really high like 4500 to 5000 rpms before shifting the check engine light is on and starts flashing when i really get on it after it starts flashing it starts to putter but it keeps going like it dont loose power at all got any ideas what it could be could anyone let me know what it could be....my guess is the idle position sensor well let me know if thats what it could be thanks

 

Get your codes read! ..and don't resurrect threads that have been dead for years!