MBC1980 Posted December 7, 2020 Share Posted December 7, 2020 Hey guys, my dad has a 1986 F150 5.0 4x4 that he ordered in Sept of 1985. It was the first EFI 4x4 off the line in Norfolk Va. Since it was new it has always had an issue with cutting off, especially on cold start. When it idles high, it will drop down and sometime stall or it will catch and stay running. Put in gear and it will stall typically. It is notorious for cutting off and not staying running and it has had that issue since it was new. No one could ever figure it out. A while back it developed a skip in the idle. When taking off and climbing hills it runs good but in overdrive or sitting idle it has a skip and that affects how the transmission downshifts and it shutters when slowing down. When accelerating even mildly its smoother and the skip goes away. So far here's some things that have been done recently. Intake and valve cover gaskets Idle air control valve Thermostat PCV valve Throttle position sensor MAP sensor Fuel pressure regulator Swapped out a computer from junk yard Harmonic balancer New belts and hoses Spark plugs and wires 02 sensor Fuel relay Oil sending unit Water pump Fuel filter is relatively new Solenoid Starter Motor was rebuilt 20 years ago and has low miles on it since rebuilt. No vacuum leaks Fuel pressure is good Not sure about compression The temp gauge stays very low and oil pressures reads very high. It has been garage kept and never been a daily driver. We've had a specialist from a Ford dealership look at it and cant figure it out. Was this a common issue with this new EFI system at the time? Thanks in advance for any help that could be provided. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 7, 2020 Share Posted December 7, 2020 Welcome, Micah! I'm sure glad you joined 'cause the others on here are much more likely to know about the EFI systems then I do. Beautiful truck as well. But here's a suggestion - copy and paste your entire post into a new thread in the main section. You may get more help there than here in the NMSH section as more people are likely to see it. So, where's home? We have a map (Bullnose Forum/Member's Map in the menu) and we could add you to that if we had a zip code or city. Link to comment Share on other sites More sharing options...
MBC1980 Posted December 7, 2020 Author Share Posted December 7, 2020 Welcome, Micah! I'm sure glad you joined 'cause the others on here are much more likely to know about the EFI systems then I do.Beautiful truck as well.But here's a suggestion - copy and paste your entire post into a new thread in the main section. You may get more help there than here in the NMSH section as more people are likely to see it.So, where's home? We have a map (Bullnose Forum/Member's Map in the menu) and we could add you to that if we had a zip code or city.Ok great thanks! On Mon, Dec 7, 2020, 10:08 AM Gary Lewis [via Bullnose Enthusiasts Forum] <redacted_email_address> wrote: Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 7, 2020 Share Posted December 7, 2020 By the way, I see you are posting via email. You can do that but it isn't advised as it brings a lot of baggage with it, as shown in the screenshot below. I've circled the "baggage" that gets copied in unless you take pains to delete it before responding. Instead of responding to the email, if you'd click the link in the email that's below the line that says "If you reply to this email, your message will be added to the discussion below:" you'll be taken to the forum and you can post there/here. And doing so won't bring with it the baggage. But that's your call. However, it is more difficult to read posts if you do reply w/the baggage and not everyone will bother to do so and you won't get the responses you would otherwise. Link to comment Share on other sites More sharing options...
kramttocs Posted December 7, 2020 Share Posted December 7, 2020 Welcome! Very, very nice truck Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted December 7, 2020 Share Posted December 7, 2020 Welcome to the forum Micah! Gorgeous truck. One thing that was common, caused stalling especially off the line, was failure of the Thick Film Ignition system. So much that Ford was forced to replace them in tens of millions of vehicles after a few deaths and class action suits. The factory placed the module on the distributor, using it as a heatsink. What's usually done to remedy that is to relocate it to the drivers side inner fender with a dedicated heatsink. FatFoxx and McCauley Racing both have kits available. This MAY be your issue. Accurate diagnosis is the first step. Link to comment Share on other sites More sharing options...
MBC1980 Posted December 7, 2020 Author Share Posted December 7, 2020 Welcome! Very, very nice truck Thanks! Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 7, 2020 Share Posted December 7, 2020 Thanks! Well done! See how clean that post is? Link to comment Share on other sites More sharing options...
MBC1980 Posted December 7, 2020 Author Share Posted December 7, 2020 Welcome to the forum Micah! Gorgeous truck. One thing that was common, caused stalling especially off the line, was failure of the Thick Film Ignition system. So much that Ford was forced to replace them in tens of millions of vehicles after a few deaths and class action suits. The factory placed the module on the distributor, using it as a heatsink. What's usually done to remedy that is to relocate it to the drivers side inner fender with a dedicated heatsink. FatFoxx and McCauley Racing both have kits available. This MAY be your issue. Accurate diagnosis is the first step. The only time the stalling happens is if its sitting and idling or sometimes but less than common is when slowing down to make a turn when not accelerating but never when driving. Link to comment Share on other sites More sharing options...
MBC1980 Posted December 7, 2020 Author Share Posted December 7, 2020 Thanks! Well done! See how clean that post is? Yes thanks for the info. I didnt realize I was replying to a thread when I saw the email response. Link to comment Share on other sites More sharing options...
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