I have a 1997 F-150 build date is June 1996 with a 4.6 V-8, I love the girl but recently she has developed some issues one is when I start it she will will run great but after it warms up and if I tap the accelerator it will idle down to about 500rpm then jump back to idle speed maybe 1000 and the warmer it gets it becomes worse. I'm guessing a temp sensor is going south but not sure. I have no warning lights but my son has an Accutron available. Any ideas? I love the posts on laptop software anything available on this old girl? She's become a stay at home freighter due to the gas prices but she turns heads when I drive her. Thanks in advance! ILPT

 

Whens the last time it had a tune up? Try changing the spark plugs and fuel filter and see if it runs any better.

 

Well, that's what I thought fuel filter never at just under 160K and plugs were changed at 100K. I'm trying to bring the old girl back to normal she deserves better than that because she still looks good I'll post pictures soon. Thanks!

 

Fuel filter is supposed to be changed every 30k.

 

Clean the tb, iat,maf, and change the fuel filter.......

 

88 Racing, I changed the fuel filter with little or no improvement, cleaned and changed out the IAC no improvement hooked up my Actron Super scanner but first cleaned TB which it was terribly dirty with little or no change found according to the manual STFTRIM1 should not stay in the negative while LTFTRIM1 is in above 10 which it was and it stayed in the negative all the time. The book says if this is the case MAF sensor is bad. Changed out the MAF assy now it idles OK! Thanks for your help! ILTP