P0303 code HELP

Had a local Toyota dealership diagnose my p0303 code and said it’s “probably” the injectors so I had them replace them with oem and I still get the code. Could it be valves? Rings? What could it be? I’m gonna take it back there and tell them diagnose it right this time.

 

Which engine?

 

They diagnosed it...I would take it back

 

P0303 is a cylinder three misfire detected, so suggesting you should change your injectors is ridiculous. Cylinder 3 injector? Maybe... clearly they didn't do enough trouble-shooting. It could be a lot of things, but I would my first guess would be plug/wire/coil. How many miles since secondary ignition components were changed?

 

2.7

 

Did they check valve clearances?

 

Plugs and wires were replaced about 6 months ago. The dual coils I haven’t replaced yet. Maybe I should switch wires on the coil to see if I get a different code. If I get a different code then it’s not the coil right?

 

Can I switch wires on my coil to see if I get the same code or a different code? Or will that mess with timing?

 

Is this a waste-spark system? I thought it was coil-on-plug....

 

You paid to get this fixed?

 

it is a coil on plug

 

yep. Not too happy either but at least I have new injectors.

 

Is there one coil per two cylinders? I thought coil per plug wasn’t till 2000

 

yes. One coil per 2 cylinders

 

Ok I think that rules out the coils as the issues. Since it’s a wasted spark, if the coil were the issue you would expect a problem on both cylinders it fires.

but you could swap coils just to be sure

 

I would start by checking the plug, followed by the wire, and as suggested, swapping coils. Valve clearance could also be the culprit, but I would expect a multiple cylinder misfire were that the case, as valves generally wear more-or-less evenly. While I don't want to cause a panic, definitely have a good look at the plug and compare it to number 1; coolant leaks from failing head gaskets can also cause single-cylinder misfires. Do you have any idea of how much it's misfiring?

 

look for cloudy oil in coolant first. gasket leak.

 

I get the code maybe 2-3 times a day and a check engine light maybe 3 times a week. I have an ultra gauge plugged in that I clear the code with.

 

Oil in the coolant, and coolant in the oil are both definite indicators, but in my experience, you often don't see that until it's a little more advanced. If you pull out #3 plug and when compared to #1 it looks clean/white-ish that's a good indication it's being 'steam-cleaned' by a very small coolant leak. If you have a boroscope you can slide that into the cylinder and have a look for drips while the plug is out.