Getting a P0303 code on my 06 xb and I'm trying to find out the source. Recently changed the spark plugs and did routine maintenance - oil, oil filter, air filter and now getting this error. Thought it might be the coil after reading some post here so I swapped out the 1 and 3 coils (or so I thought) to try and find out if the source of the error. Light came back on and I had it rescanned and again have the P0303 code. Now it's making me wonder if I changed the correct coils. Have looked around for the cylinder numbers and can't seem to find anything on it. I'm assuming that if I'm looking at the engine from the front they go in order from left to right 1,2,3,4. Is that correct? If it is then I switched the coils correctly and I'm having another issue. Used Lucas in it to see if maybe there was a clogged injector but code came back. Could it be the injector? Any ideas would be greatly appreciated.

Everything is still stock on this xb.

 

Firing order should be

1-3-4-2

Cheers,
md

 

A number of problems can drive the 0303 code (misfire in cylinder 3) (1-2-3-4, left to right):
Engine wire short or broken
bad connector
bad ignition
bad injector
MAF problem
low fuel pressure
coolant temp sensor
low compression
valve clearance
valve timing
PCV hose connection or pcv hose
Electronic Control Module

Are the plugs seated? connectors connected? Hoses connected?

Start with the cheap stuff and the stuff you touched and go back over the job.
md

 

Thanks Cherry-8.
I just used a hand held tester. Would dealer be able to pinpoint it better with their diagnostics or would that just start eliminating things till the find the right one? Strange thing is that it drives great for sometimes a couple of days but then it throws the code and starts to sputter and feel like its going to die while stopped and in gear. Or I can just drive it a short distance and stop and then restart it and it will start. I'm just am trying to avoid a high repair bill like I always seem to get from the dealer. I'm no mechanic but it would seem to me that if it's something with the MAF, ECM or one of the other sensors wouldn't it be more vague maybe code P0300? I wouldn't think it would affect just a single cylinder but like I said I'm not a mechanic.

Nice Xb by the way - looks just like mine.

 

Cyl1 is closest to the belts, #4 near the trans. The problem has to be with the part specific to that cylinder. So most likely it's the coil, plug, injector, internal cylinder problem.

 

Reactor that's what I was thinking. I just put in new plugs and I swapped the coil from one to three and it's still giving me the same problem on #3. Think I will have to take it to the dealer this time. Don't know what else to do. Does anyone know if something like this is covered under the powertrain warranty?

 

What plugs did you use? If it was a Bosch plug, put your oem back in and you won't have the code.

 

Bearcave - Used NGKs V-Power spark plugs - recommended for this vehicle.

 

Just an update. Took it to "a guy" and was told the injector was bad. $300 for the injector and labor. I looked at how to do it online but figured it was better left to the experts. Seems to be running good now but very cautious about every little thing I hear or feel now - thinking something else is going to go wrong! Will be watching my mileage to see if it gets back to where it's supposed to be. Thinking about replacing the current air filter with a cold air one. Would that cause a problem being in the Chicago area with the winters we have here?

Thanks