Engine code P0303 misfire #3 cylinder

Tiny
CAPTAINWISCH
  • MEMBER
  • 2000 DODGE DAKOTA
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 15,500 MILES
I have been getting the engine code P0303 with the check engine light. When this first started I changed the spark plugs, plug wires, rotor and cap. The check engine light turned off. The truck ran fine. After a month or so the check engine light came on again, same code P0303. I changed all six injectors, check fuel rail pressure (all to spec.) And cleaned the throttle body along with the Idle air intake motor, and new throttle body gasket. After this the truck ran great, getting better milege with the injectors. After a month or so the engine light came on again, same code P0303. The only thing I can think of is to replace the coil, check the plugs again, and maybe replace the Air Mass Intake sensor. Would these help? Do you have any sugestions? Their isn't any sign of burning oil or coolant coming from the exhaust, its clean. I am all out of ideas Please help.
Monday, October 25th, 2010 AT 7:50 PM

3 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hi Captainwisch, Welcome to 2carpros

P0303

This misfire is only affecting (1) cylinder which is no.3-Have you done a compression check on no.3 both wet and dry tests-let me know the results-could be a connection problem at the cap and plug end on it, injector seal not seated properly,-if its the coil it'll be affecting the other cylinders same goes to the EGR and MAF.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Lets start by checking the camshaft and crankshaft sensors-inspect and test these sensors it tells the computer which plug and injector to fire upon and report back with the end of results-we start here
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Monday, October 25th, 2010 AT 9:05 PM
Tiny
CAPTAINWISCH
  • MEMBER
  • 4 POSTS
Rasmataz,

Sorry it took a while to get back to you with the answers. I just did a wet/dry compression test on cylinder #3. The results dry were 80psi and wet was 100-120psi. All the other cylinders dry tested at 130-150psi. Does that mean the valves in #3 are bad? What should I do now.
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Tuesday, November 23rd, 2010 AT 12:53 AM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
The problem is low compression you found the problem. Sounds like it is time for a valve job.
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Tuesday, November 23rd, 2010 AT 2:50 AM

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