DTC P0303

IYAOYAS_AO

MEMBER
1997 DODGE RAM
V8
4WD
AUTOMATIC
138,000 MILES

I keep getting this code and it erases easy. This is what I have doe to the truck

i have changed the spark plugs, wires, distributor cap, distributor.

what I have seen, when I tow a trailer the light goes away, when I clean the fuel injection (stp) the goes away for about a day.

the engine does not shack or the act like it is missing a cylinder when on.

any ideals?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

More than likely you have a leaking injector. We can confirm this by checking the o2 sensor voltage and seeing if it is rich on that bank but based on what you are seeing I would go ahead and replace that injector.

Here are a couple guides that talk about this issue and give more detail on possible causes:

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

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

However, due to what you are seeing with the fuel cleaner and added load the misfire goes away, that is pointing directly to an injector issue.

Here is a guide that will help with replacing it:

https://www.2carpros.com/articles/how-to-replace-a-fuel-injector

Below is the process from the manual on how to replace the injectors. Please let us know if you have other questions. Thanks

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