Missing after tune up
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Junior User
Joined: Mar 2002
Posts: 84
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From: Grafton USA
Missing after tune up
Hey guys I have just bought a 1990 F-150 w/ the inline 6 and a 5 speed.. It has a 3.08 gear in the rear. My question is I just did a tune up tonight that consisted of AutoLight Plugs and Wires, new distributor car and Rotor Button, PVC valve, and Fuel filter. Before I did this the truck was missing kinda bad. Mostly around town driving a some highway driving. Well I did the tune up and it ran fine until it warmed up a little bit and then it started missing again around 20 -35 mph range. Well it quite doing that after I checked everything over again but it started back up around 45-55mph. This is not making sense to me. I gaped the plus to about .044 to .045. Then I went and bought some STP fuel injector cleaner and filled the tanks up w/ 89 octane. Can anyone tell me if they have had this problem before and what needs to be done. I don't think that the 02 sensor has been checked but I will have to check the maintence records.. I hope someone can help me. Thanks for any input
Andrew
Andrew
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Joined: Dec 2001
Posts: 2,017
Likes: 2
From: Southeast FLA
Missing after tune up
Wow, my first guess would have been a loose plug wire, but you changed them all, plus the other things, and you're still getting a miss.
I would check the wiring that goes to each injector to make sure each is connected nicely, and that no wires are frayed.
Check for rotten, cracked or broken vacuum lines, too.
Since this happened at different speeds, is there any chance it was in different gears, but the same RPM that the missing started?
Best,
I would check the wiring that goes to each injector to make sure each is connected nicely, and that no wires are frayed.
Check for rotten, cracked or broken vacuum lines, too.
Since this happened at different speeds, is there any chance it was in different gears, but the same RPM that the missing started?
Best,
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
Missing after tune up
My 90 developed a mystery miss that seems to be from a lean condition. It went away when I swapped in the larger fuel injectors. A lean mixture is harder to get burning than a rich mixture, so a weak ignition component could be to blame. What brand of cap and rotor did you install? Lots of the parts store stuff is junk. Lots of Ford vehicles develop this problem because of corrosion on the coil tower. Pull off the coil wire and see if your coil is corroded under there. Another thing to try is going out after it gets dark and watch under the hood with the truck running. If you have spark energy escaping somewhere it will appear as a blue glow. Spraying some water on the cap and plug wires can sometimes make the problem reveal itself. At my last tuneup I used Autolite 5125's and actually got bad spark plug installed in #3. There was no sign of any problem on the outside of the plug, but replacing it was all it took to fix the problem. Did you use plug wire grease on all the wires when you put them on? It helps to keep the spark going where it's supposed to.
Thread Starter
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Junior User
Joined: Mar 2002
Posts: 84
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From: Grafton USA
Missing after tune up
Well I had a feeling that it was the injectors but I was kinda hoping that it wasn't but ohh well.. Soo how hard is it to put new injectors in? Would it be best to put 6 new ones in instead of just one? Would it be better to go w/ a larger one? What brand should I use??.. Thanks for all the input!!
Andrew
Andrew
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