Hello all, hoping someone here can help me (fingers crossed) I have a 2014 CX-5 touring and I have had some issues with misfires recently. It all started with a misfire in Cyl 3, this happened shortly after a tune up with new Mazda spark plugs. I replaced the bad #3 coil with a new one and the truck ran fine for a few weeks, then got another misfire in cyl 3 again and also found that new plug in #3 was fouled. Noticed also that she is burning oil pretty good but no smoke from tail pipe or any leaks etc. I Replaced coil again and replaced the fouled plug with another new plug (these are all Mazda parts not aftermarket just an FYI) and did an oil change. Car was fixed for a few days than it started bucking and hesitating. Thinking there may be something going on with the head gasket, so I checked the head gasket and didn't find any issues with standard testing methods (visual inspection, checked for bypass of gasses in the cooling system). She has been running but not well and now I am getting codes for random multiple misfires and a code for a misfire in cyl 1 and an over heat code for the 02 sensor. I wanna take the truck to someone and have them go through it but I'm worried that there is something wrong internally and would rather not dump a bunch of money into it to find out there is a catastrophic issue. Truck has 140K but has been pretty issue free for the life of her so I am not sure how to proceed. Any suggestions? Thanks in advance.

 

Welcome to the forum.

 

STOP replacing parts unless you test and varify they are bad.
The engine must be health checked before assuming anything.
1). Compression test. Rotate engine no more than 5 cycles per cylinder.
2) If any cylinder is lower than 10% of the highest repeat compression test wet method.
3) Perform a cylinder leak down test.
4) Perform a cooling system pressure test.
5) Perform a chemical colling system test

You results will tell you the health ststus of the engine and posibly where you isseu is if mecahnically related to the LONG BLOCK.

 

Thanks, I was a member a long time ago for my 3, but my acct must have expired I have not had any issues with this vehicle in all the time I have owned her so I never needed to reach out.

 

Well welcome back as a returning member !