Need help
Thread Starter
Junior Member
Joined: Jun 2014
Posts: 9
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Need help
Truck started have some issues when I got up around 50 to 55 mph, it started sputtering and shaking like a coil had gone bad. Plug it up and got a P0301 P0351 P0355. Showing misfire in cylinder 1. Changed coil and plug and now truck seems to be running worse than before. I'm at a loss. Could it be a fuel injector issue or ???
05 5.4l 3v s.crew lariat
Joined: Oct 2009
Posts: 3,505
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From: fl
This engine requires all to be perfect in spark area
Plugs must be torqued in 25 to 28 psi / don't guess at this . . New boots must be changed and coil contacts all cleaned . New plugs can break being forced thru carbon on snout area of head , Clean that carbon out with carb cleaner .
That carbon breaks plugs coming out it can break them going in . Loose plugs are common on this engine ,even shops are screwing this up , check them all . . All boots and springs should be changed . That's 30,000 volts passing thru that boot if it jumps to the head at all it will misfire .
Use a little dielectric grease on boot ends , not on connections-- it is an insulator .
Finally there have been a lot of reports of bad out of the box new mc plugs , maybe because they were forced into carbon????
If you are using anti -sieze be careful as it contains metal and can short out plug keep your fingers clean .
The cop bolts have been snapping off due to corrosion ,you might like to put some anti sieze on them . Make sure your cop plugs are snapping on, if not replace plug . Some guys are temp tie wrapping them.
That carbon breaks plugs coming out it can break them going in . Loose plugs are common on this engine ,even shops are screwing this up , check them all . . All boots and springs should be changed . That's 30,000 volts passing thru that boot if it jumps to the head at all it will misfire .
Use a little dielectric grease on boot ends , not on connections-- it is an insulator .
Finally there have been a lot of reports of bad out of the box new mc plugs , maybe because they were forced into carbon????
If you are using anti -sieze be careful as it contains metal and can short out plug keep your fingers clean .
The cop bolts have been snapping off due to corrosion ,you might like to put some anti sieze on them . Make sure your cop plugs are snapping on, if not replace plug . Some guys are temp tie wrapping them.
Thread Starter
Junior Member
Joined: Jun 2014
Posts: 9
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Update, I was reading somewhere about the p0301 code could have something to do with the MAF. Well after disconnecting the connector from the MAF it acted like it wanted to die but didn't. Ran for about 5 seconds and then died. I put the connector back on and proceeded to restart the truck. Once I crank the truck I noticed the check engine light was off and the truck had an idle that was smooth as silk. WTH???? Jumped in and took for a spin and runs like a charm. I did notice a slight shudder going up a steep hill but nothing like before. Probably gonna take the injectors out and give them a good cleaning. Any suggestions on what to use to clean them?