which engine? ; again, and WHAT ENGINE ???????
your fixing and engine and don't know what's there? really?
303 means misfire.
but more accurately it means weak combustion
and can be cause by 3 things. or more.
1: bad spark , be it the plug or wires, or coil
2: low compression, lots of ways. 10 or more, ask.
3: bad air fuel ratio to that cylinder 3, air leaks?
the ECU discovers this with the spark monitor
this monitor (runs all the time) it sees, the crank shaft
not accelerate fast enough, (weak power stroke on #3)
that is all you need to know on P030x codes.
if spark is prefect
and AFR good.
then it must be compression, right?
even water leaks to the combustion chamber can do this.
it is misfiring, that you can bank on.
no engine posted, why do that?
all we know here, is a body. a 05 GC.
ill quote the fsm
i toss coin, lands on 3.7
the FSM listed items for 303, some are IFFY (comment
- INTERMITTENT MISFIRE #3 only. !!!
- VISUAL INSPECTION (of spark and injector parts)
- (F142), (K334) ASD RELAY OUPUT CIRCUIT (i disagree)
- ENGINE MECHANICAL PROBLEM (50 causes)
- IGNITION COIL
- COIL CONTROL CIRCUIT
- SPARK PLUG
- CHECKING FUEL PRESSURE (why only 1 cylinder?)
- FUEL PUMP INLET STRAINER PLUGGED (ditto)
- RESTRICTED FUEL SUPPLY LINE (ditto)
- FUEL PUMP MODULE (ditto)
- CHECKING FUEL LEAK DOWN (injectors leaks)
- FUEL INJECTOR (injectors sticks)
- INJECTOR CONTROL CIRCUIT (shorts or opens in the line)
- PCM (last , if ever. i bet not it)
Basics is better.
1: SPARK BAD.
2: FUELING BAD. (LOTS OF WAYS , FUELing OR AIR LEAKS)
3: BAD COMPRESSION, or even water leaks or cam lobe damage
or valves in head bad. ,
does your engine use COPS? coil over plugs????
why not say what engine.
did you replace the spark plugs and use the correct type
and gap them per the hood EPA sticker (look up)
and if it has COPS, did you at lease make sure the COP boot
on #3 is brand new? if not why not?
using the old boots on #3 is wrong, idea. they all fail. soon.
the 3.7 has COPS
put new boot on it. (buy them, if possible. (i carry spares at all times)
then look in the wells. are the wells full of oil or water. BINGO.
did you even look there?
the one hard part of misfire is , is the AFR, air fuel mix ok on #3
and compression, W.O.T. the tool is like $20 and 15min work.