97 5.4 missfire
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97 5.4 missfire
OK so this is my first post and I'm at my wits end with this problem. I just picked up 97 F-150 4x4 with the 5.4. It's been sittin up for 4 years with a bad fuel pump... I swapped out the pump and cleaned the tank and it fired right up... I noticed it had a miss or two so i started unpluging COPs and injectors and found that #3 and #6 were the bad ones. So i head on down to the parts house, Grab two coils, new plugs, fuel filter, B-12, and carb cleaner. Swap out the above and clean the throttle body (unplugged the Bat) pulled the injectors cleaned em all. And im still not hittin on those cylinders... I can take off and itll run but then start to backfire and just lay down on me... All I can think of is maybe the wires feedin my COPs are bad... Any IDEAS? Thanks for any help
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OK, so you isolated the dead cylinders, #3 & #6. With the truck sitting that long, it's more likely to be collapsed lifters or sticking valves. What's the oil pressure ? Any unusual noise under the valve covers ? You say it backfires. Is that through the exhaust or the lower intake ?
It could possibly be no power to the 2 coils, and a cheap noid light will tell you that ( any evidence of mice chewing on the harness ? What is the engine vacuum, if and when you can get it to hot idle ?
Dave
It could possibly be no power to the 2 coils, and a cheap noid light will tell you that ( any evidence of mice chewing on the harness ? What is the engine vacuum, if and when you can get it to hot idle ?
Dave
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Oil pressures fine judgeing by the guage. I changed the oil and ran some sea foam in with it to free up what I could. Hopein that knocks out some of the smoke. No noise really other than your usual ticks and clicks. Back fires through the exhaust and found a vacume leak but fixed it first thing..... forgot to mention that. dosent look like anythings got ahold of the harness. if i does go down on me i just kill the truck for a few mins and itll take back off....
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Two things- The noid lights were to check for power to the injectors, not the coils. Second, was the truck yours when it was parked 4 years ago ? I know people that have changed the fuel pump for an attempt at repairing the same problem you have now. Might the pump have been good, and the truck still has the same problem ?
I think that engine has the IMRC valve under the intake. Controls would be behind the intake lower plenum. Check those hoses first ( if you have this), then run a vac test on the controls themselves. I believe they start to function at about the RPM range you would be at when the engine falls flat. Just a thought.
Dave
I think that engine has the IMRC valve under the intake. Controls would be behind the intake lower plenum. Check those hoses first ( if you have this), then run a vac test on the controls themselves. I believe they start to function at about the RPM range you would be at when the engine falls flat. Just a thought.
Dave
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Thrower20
1997 - 2006 Expedition & Navigator
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Apr 6, 2010 01:32 AM
