1998 F150 cylinder misfire - I have an incredibly frustrating problem. My old girl seems to like to have misfires with cylinder 7 - has anyone had this problem? It is always cylinder 7 - I have replaced both coil packs, plugs, wires, egr, injectors, fuel filter, fuel pump etc. I have realized through other posts that FoMoCo has made life simple if we just purchase OEM parts. I will try that when I purchase my new parts.

But, why is it always cylinder 7 that has issues. I checked my plug gap after I replaced all plugs. I have maybe 3,000 miles on the new plugs and cylinder 7 gap was .65 - i regapped to .54 and she seems to run better (for now) what causes the gap to blow out like that?

When I was leaving my friendly neighborhood parts store after they read my codes for free :-) - the truck bucked and spat like an angry imp - the dash lights went out. I threatened the truck with a car crusher and I was able to get her home.

After tenuously checking and replacing every relevant fuse (which were perfect and not blown) for the dash lights, I also noticed during testing that the parking lights do not work now.

The other accessories that are linked with the not blown fuses work fine. I am confused (again) as to what has gone wrong with the parking lights and the dashboard.

Any helpful advice would be appreciated. I love my truck and have 145,000 miles on her. But she is starting to wear on my nerves with all the hoopla she is causing.

I would hate to have to buy a Chevy

Thanks in advance

 

what kinda plugs are you using? Modulars are pretty picky about the plugs.. they only like motorcraft ngk and denso's really.. #7 is prone to getting road water spashed on it especially if the shield that attaches to the inner fender is missin..

 

Thank you for your help - I have NGK installed - I have the inner shield still in great condition. I did notice some wetness so I will check the shield better. Did you have any idea as to why the gap would open up so greatly? I am going to order new OEM wires and fresh motorcraft plugs. Are you aware of any place online or store where I can get them cheaper than the dealer. Going to the dealer is dangerous as they have nice new trucks there..........

 

last I saw the motorcraft plugs were 2.99 at Rockauto.com.

 

they also carry motorcraft wires at a discount..

 

thank you for your assistance, I shall purchase these items and see if magic happens.