Question about 2002 Mazda MPV
I have a misfire in cylinder 3. What can I do to fix it?
I recently had that (po303) misfire in cyl. 3 on my 2002 Mazda MPV LX with the 6cyl. 3.0 ford duratec engine (the only engine installed that year). 75k miles. The engine was studdering while at idle and upon accelleration. It was worse when the AC was on. The check engine light came on. I went to Advanced Auto Parts. They loaned me a code reading handheld computer. An Actron OBD II. PO303 misfire in cyl.3 was the verdict. I then got on the internet to do some research. Found that the problem could be a number of things. Coil packs and/or wiring harness, spark plugs, egr valve and/or ports, fuel pump or filter, fuel injectors etc. etc.. I decided to try what I thought was the simpilist remedy first. I purchased new spark plugs, retrieved some tools from the garage and opened the hood. Though I've performed all the other routine maintenance items like oil changes, battery maintenance, air filter etc., I never really looked for or noticed the spark plugs or their location. The front bank of 3 plugs was a breeze to change out but the rear bank....well they havn't been changed yet. Not so simple. At that point I decided that since I would have to remove the intake manifold and all the wires,hoses and etc. would have to be unattached, I might as well change the 3 coil packs and recondition the 6 fuel injectors while I had it apart. The cost and hassle of those fixes then lead me back to do what my old school, auto mechanic all his life father, alway told me. "Look at the easy fixes first". Many of us think that since everything nowadays is so complex that the fix must be complex also. Well, I then purchased a bottle of Chevron Techron Fuel Injector Cleaner. So many other brands were on the shelf to choose from. Seafoam, Lucas, Shell, CRC, STP, etc., etc.. Through netsurfing I discovered an old CARTALK Q & A. They kinda gave a halfhearted nod to the Chevron product. It stuck with me so I tried it. Within 10 miles the engine began to run better. The more I drove the better the performance. The Check engine light went off. No more misfire in cyl. 3 and no more code po303.
Posted on Dec 07, 2008
Try gapping your plugs. Book says around .040, but proper gap on a MPV is .052-.055... That was my problem. New gap fixed it... after I replaced the wires, coil pack, checked for vacuum leaks, sea foam in tank.. etc.. etc... turns out it was just a stupid mis-print in the wally world book... new gap and all is good.
Posted on May 26, 2009
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Posted on Jan 02, 2017
Posted on Feb 14, 2009
i had asimiliar misfire on my 2000 windstar.the first thing to check is a broken valve spring by taking off the valve cover the other is a o2 sensor bank 2 i believe is the downstream.if not the valve spring then either the coil pack or thecontrol module. either way it is fairly inexspensive
Posted on Mar 08, 2009
You will need to find the firing order of the engine you have to determine where Cylinder 3 is located.
Please read this link for more informationhttp://www.obd-codes.com/p0203
Posted on Jun 03, 2010
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