87 F150 I6 Engine Miss
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87 F150 I6 Engine Miss
I've been trying fix a '87 F150 4wd truck with the 300 6 , 4 speed manual, that suffers from very poor idling and now has developed an engine miss. When it is cold, the engine also stumbles terribly (almost undriveable) until you reach 2100 rpm. Once operating temperature is reached, stumble is still there but less drastic.
Had the fault codes read and they showed:
1) engine computer can't control idle
2) egr valve not working (no gas flowing)
3) O2 sensor showing lean
Saturday, I was towing a light load with the emergency flashers on. I'm 99% convinced that the engine miss worsened with the flashers on. Does this make any sense?
Plan is to try and remove the EGR valve and sevice/replace (if I can get it off) and look for an intake or vacuum leak.
Have changed plugs & wires, MAP sensor, TPS sensor, both low pressure fuel pumps (dual tanks)& high pressure fuel pump in the past year.
Any other suggestion/recommendations?
Thanks
Kevin
Had the fault codes read and they showed:
1) engine computer can't control idle
2) egr valve not working (no gas flowing)
3) O2 sensor showing lean
Saturday, I was towing a light load with the emergency flashers on. I'm 99% convinced that the engine miss worsened with the flashers on. Does this make any sense?
Plan is to try and remove the EGR valve and sevice/replace (if I can get it off) and look for an intake or vacuum leak.
Have changed plugs & wires, MAP sensor, TPS sensor, both low pressure fuel pumps (dual tanks)& high pressure fuel pump in the past year.
Any other suggestion/recommendations?
Thanks
Kevin
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Joined: Feb 2000
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87 F150 I6 Engine Miss
I have a 82 f100 with the inline six, I had the same type problem I thought it would be something major but my uncle hooked his scope to the engine and it turned out to be the number 4 spark plug had gone bad. The engine would barely pull hills and would barely hit 55mph. After changing the number 4 plug everything smoothed out. Also my uncle adjusted the air/fuel mixture. I believe you said code showed lean mixture which would damage plugs.
Steven Willis
Steven Willis
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From: Linwood, N.J. USA!
87 F150 I6 Engine Miss
Kevin, Check for vacuum leak. All lines. It does sound like that replacing the EGR valve will correct the problem. Make sure that you have good vacuum to the EGR valve actuator. As for the flashers effecting the operation, is your battery and charging system in good shape? I have seen a bad alternator drain the battery and make an engine run bad to the point of backfire. When the computer does not have enough electrical power, it will make the engine run real poor. A bad wire on the charging system can also do this. Just a thought. Good luck.
Jakegypsum // Ford fleet, soup to nuts.
Jakegypsum // Ford fleet, soup to nuts.
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87 F150 I6 Engine Miss
Concerning the flasher deal, I do know that certain GM pass. cars with 3.8L V6 did experience spark known during flasher operation...but I can't say that about any Ford models. Now, of course I'll tell you to check all vacuum lines as detailed on the underhood decal. Next you need to clean the throttle body and Air Bypass Valve. To properly clean the throttle plates, hold them wide open and using a toothbrush soaked in solvent, scrub the bores and the plates as best you can while flushing the build up away with a rag and spraying Intake/Throttle Cleaner. The Air Bypass needs to removed for a brushing , so pick up a new gasket before you get started just in case you break the gasket. With these all cleaned and ready to try, it will be a 'lil difficult to fire up the engine because of the solvent that has accumulated past the throttlebody, but it's a good thing actually. When you do hear the engine begin to fire off, press the gas pedal back and forth until the engine will clear up. The good thing is that the accumulated solvent will make the computer go full rich for the first few moments because of the solvent that is hard to burn and will force a reset on the idle speed and quality by the time the solvent is all burned off ! Changing the plugs after the cleaning is the best time to do so, just for reassurance.
Phil
Phil
