Hi,
I bought a used Mazda6S V6 (manual transmission) with 97000 Mi. Before buying the car, I had AAA do a pre-purchase inspection. They found a few items - the valve cover gasket needed replacing, new engine mount, cracked boot. They assured me the engine seemed to be running fine and that there were no pending codes etc... I bought the car and had AAA replace the valve gasket. My regular mechanic did the rest of the work. A few days after the repair, the car started hesitating/bucking under acceleration (particularly in 2nd). My mechanic said it's not unusual - might be the clutch wearing in to the way I drive etc.. I took the car home and looked for codes with my OBD-II blue-tooth scanner - it had a pending P0304 - Cylinder 4 misfire. My mechanic told me I should clear it out and come in if it re-appears. Sure enough, the next time I drove it, the car was still showing the same bucking/hesitation under acceleration and this time I got a Check Engine Light. My blue-tooth scanner indicated the same P0304. When i took it into my mechanic, he could only pull a P0300 (random cylinder misfire). He told me that he needs me to drive more before he can diagnose it. I took it to another mechanic (based on a recommendation from a friend). They had the same issue - all they could pull was a P0300. The guy swapped two coil-packs in front. He was unsure which cylinder 4 was - he thought it was the middle. I think it's the leftmost (when viewed from in front of the engine). I tried pulling the code with my phone but all that I could get was a P0300. He agreed that it was a misfire and that he could feel and hear it. On the way home, I stopped into Advance Auto Parts - they managed to pull a P0304 but pending (i.e. the CEL hadn't triggered). After driving away from the AAP, the CEL came back on. I can try reading the code again, but what the heck is going on? I'd have hoped that swapping the coil-pack would have shifted the error to a different cylinder. My first mechanic said he checked the front row of plugs and they were fine and firing. Can anyone please help?
I bought a used Mazda6S V6 (manual transmission) with 97000 Mi. Before buying the car, I had AAA do a pre-purchase inspection. They found a few items - the valve cover gasket needed replacing, new engine mount, cracked boot. They assured me the engine seemed to be running fine and that there were no pending codes etc... I bought the car and had AAA replace the valve gasket. My regular mechanic did the rest of the work. A few days after the repair, the car started hesitating/bucking under acceleration (particularly in 2nd). My mechanic said it's not unusual - might be the clutch wearing in to the way I drive etc.. I took the car home and looked for codes with my OBD-II blue-tooth scanner - it had a pending P0304 - Cylinder 4 misfire. My mechanic told me I should clear it out and come in if it re-appears. Sure enough, the next time I drove it, the car was still showing the same bucking/hesitation under acceleration and this time I got a Check Engine Light. My blue-tooth scanner indicated the same P0304. When i took it into my mechanic, he could only pull a P0300 (random cylinder misfire). He told me that he needs me to drive more before he can diagnose it. I took it to another mechanic (based on a recommendation from a friend). They had the same issue - all they could pull was a P0300. The guy swapped two coil-packs in front. He was unsure which cylinder 4 was - he thought it was the middle. I think it's the leftmost (when viewed from in front of the engine). I tried pulling the code with my phone but all that I could get was a P0300. He agreed that it was a misfire and that he could feel and hear it. On the way home, I stopped into Advance Auto Parts - they managed to pull a P0304 but pending (i.e. the CEL hadn't triggered). After driving away from the AAP, the CEL came back on. I can try reading the code again, but what the heck is going on? I'd have hoped that swapping the coil-pack would have shifted the error to a different cylinder. My first mechanic said he checked the front row of plugs and they were fine and firing. Can anyone please help?
