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dead miss under load


dirtymike

Well-Known Member
U.S. Military - Veteran
Joined
Dec 30, 2010
Messages
527
Age
64
City
knoxville TN
Vehicle Year
1987
Engine
2.9 V6
Transmission
Manual
Total Lift
1 inch spacers
Tire Size
P23575R15
My credo
Do unto others then Split-probasti me et chognuisti me
1987 ford ranger 4x4 manual trans(FM145) 2.9 litre. Ranger sit for a few weeks with stabil in the tank. It was running on all 6 cylinders when it was parked. Went through the top end last winter. Seems that it drops half the cylinders when it is under load. Idles rough sometimes. Seafoamed it, same thing. ran good for a few minuites then started missing. Has a little back fire, not much. It just started missing? Oh well, any suggestions from TRS would be appreciated. Dirty
 
Seafoam does nothing.

Sounds like injectors are gummed.

You can try to clean them. Better to replace.

 
I rebuilt them last winter. Wonder if the rust built up in the rail that fast and made its way to the screen in the injector.
 
2.9l

Its a TFI module problem, almost always
I would expect clogging injectors to stay clogged, so runs poorly, and stays running poorly, doesn't get better.......ever

If it runs better cold then also could be TFI, possibly O2 sensor, or ECT sensor

Try running at WOT(wide open throttle) and see if misfires clear up, if so change O2 sensor, the computer ignores O2 sensor(s) at WOT, just runs on preprogrammed mix tables

If it still misfires at WOT then TFI, always comes back to TFI, lol


If you have a vacuum gauge check engine vacuum, 18-21" is expected
Check vacuum line to MAP sensor, no leaks
 
Try draining the gas and refilling with fresh before you do anything.

I know you used sta-bil but i would still start with the eaiset component.
 
Even with Stabil, gas goes bad. I agree, change the gas.
 
Gas was new two weeks ago, pure gas with stabil. I use it every time i fill it up. tank is half full. pumped enough out and ran it in the lawn mower. drain it anyway, use it in the tractor. Got a extra TFI, know how to test them off the truck. Thanks Dirty
 
Changed gas, nothing. Changed TFI, nothing. Started pulling plug wires running(Shocking) to find the dead cylinder. Number 2 plug will not fire. Number 2 Spark plug wire is hot, ouch. Autolite 765. Now to find them.
 
Before pulling the plug disconnect coil spark wire, so no spark/no start
Then crank the engine over a few times
Now pull out #1 and #2 spark plugs
#1 tip should be WET with fuel, as should #2, if not then injector issue

So 2 birds with one stone
 
Thanks RonD, wish i would have thought of that before the shocking experience. I bet your right on the injector on #2. seems it was dry when i pulled it out but had a good color. I don't remember if you can remove the injectors one at a time. I think i will have to remove the plenum. Going to try your suggestion when this rain lets up. Thanks Dirty
 
Well it seems more than just number 2. three of the plugs were barely wet. injectors clogged again. They are all clicking but fuel is barely going through. I bet its a rusty fuel rail. Got to pull the plenum first. Dirty
 
three of the injectors had rust build up in the screen. Got them cleaned and spraying uniformly now. Guess i better change the filter to. Dirty
 
Acid wash the rail.
 
Is that with muriatic acid?
 

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