automation man
Member
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- 2009 Mazda CX-9 Sport AWD
First time here in this forum; I hope somebody can help. I have a 2009 CX-9 Sport AWD w/50k miles (very low miles). 2 months ago, wife noticed engine running very rough and check engine light came on (solid). Checked with my scanner and found (2x) P0306 [cylinder 6 misfire]. After Google search, found many saying plugs need to be changed between 50-60k. No problem changing front 3, but the rear 3!?!? Had to go in for inspection anyway, so paid mazda to do it & troubleshoot the code. They said the coil pak on cyl 6 had "internal fault" and replaced, along with all plugs and new PCV valve.
1 week later, rough startup, check engine light, and heavy white smoke coming from both exhaust pipes (outdoor temp 80-90F - this was not startup condensation!). Took back to Mazda dealer. Found P0306, P0316, P0206 codes. Replaced cyl 6 injector.
3 weeks later, noticed the engine running VERY HOT with A/C on, almost overheated. Engine running rough again, check engine light on, P0306, AGAIN!!! Removed oil cap and found white "gunk". Took back to dealer. Removed (new) spark plug from cyl 6, found "carbon deposits". Swapped plugs with cyl 4 and got misfire code on cyl 4; determined bad spark plug. Replaced with new spark plug. Performed compression test on all cylinders, ~ 175psi each. Added 1/2 gallon of FL-22 coolant and performed pressure test; no leaks. Mechanic said the white gunk was just condensation. Where did 1/2 gallon of coolant go and why did I experience 2 episodes of heavy white smoke??? No answers
A few days later, engine running rough on startup, check engine blinking, then solid. When I say running rough, I mean bucking, shaking. Back to the dealer. More P0306 codes. They called Mazda, who said to replace the PCM. Currently waiting for the part to arrive.
Has anyone ever heard of anything like this?? This vehicle is driven primarily on very short trips (2.5 miles each way to work + normal weekend driving).
I've asked multiple times if they've checked the crankshaft position sensor and pulley, but they insist there would be a code if there was a problem. Also still no answer as to where 1/2 gallon of coolant went. I asked them to change the oil again and inspect for any signs of coolant (less than 500 miles since last change).
What am I missing here??? The thing they haven't checked is the intake manifold gasket. In my experience, lost coolant & white gunk = one of 3 things:
1. Intake manifold gasket
2. Head gasket or cracked head
3. Cracked engine block
HELP, PLEASE!!!!!!
1 week later, rough startup, check engine light, and heavy white smoke coming from both exhaust pipes (outdoor temp 80-90F - this was not startup condensation!). Took back to Mazda dealer. Found P0306, P0316, P0206 codes. Replaced cyl 6 injector.
3 weeks later, noticed the engine running VERY HOT with A/C on, almost overheated. Engine running rough again, check engine light on, P0306, AGAIN!!! Removed oil cap and found white "gunk". Took back to dealer. Removed (new) spark plug from cyl 6, found "carbon deposits". Swapped plugs with cyl 4 and got misfire code on cyl 4; determined bad spark plug. Replaced with new spark plug. Performed compression test on all cylinders, ~ 175psi each. Added 1/2 gallon of FL-22 coolant and performed pressure test; no leaks. Mechanic said the white gunk was just condensation. Where did 1/2 gallon of coolant go and why did I experience 2 episodes of heavy white smoke??? No answers
A few days later, engine running rough on startup, check engine blinking, then solid. When I say running rough, I mean bucking, shaking. Back to the dealer. More P0306 codes. They called Mazda, who said to replace the PCM. Currently waiting for the part to arrive.
Has anyone ever heard of anything like this?? This vehicle is driven primarily on very short trips (2.5 miles each way to work + normal weekend driving).
I've asked multiple times if they've checked the crankshaft position sensor and pulley, but they insist there would be a code if there was a problem. Also still no answer as to where 1/2 gallon of coolant went. I asked them to change the oil again and inspect for any signs of coolant (less than 500 miles since last change).
What am I missing here??? The thing they haven't checked is the intake manifold gasket. In my experience, lost coolant & white gunk = one of 3 things:
1. Intake manifold gasket
2. Head gasket or cracked head
3. Cracked engine block
HELP, PLEASE!!!!!!