ok so the other night i was driving home and i miss shifted from 5 to second instead of 4th. i kno i F#@$ed up now i need to figure whats wrong in order to fix it. so the codes I'm getting are p2004 and p0303. misfire cylinder 3 and imrc stuck open bank 1. i regaped all the plugs and cleaned out the throttle body (which had at least 3mm thickness of carbon build up on it, literally sat there for an hour scrubbing with a toothbrush and brake cleaner) anyways I'm still getting p2004 and instead of p0303 I'm getting p0300. i checked compression cylinder 2, and 3 are at 78psi and 1 and 4 are at 103psi

the car is acting weird i think the timing might be off but i was told the chain cant jump n if it does you would see a hole in the cover? i do kno the chain can stretch but I'm not hearing any chain chatter from timing cover. the symptoms are starter spins a few seconds then engages the flywheel, car has power but literally wants to die on idle feels like a vacuum leak. any thoughts.

now this is the first mazda 3 I'm working on had a bimmer and an mx3 b4 so i also need to get my hands on a workshop manual.

all help and input is greatly appreciated

thanks guys

 

To me at least, the low compression on cylinders two and three would mean it's time for a Cylinder Leak-Down test. That way you can pretty easily figure out whether you've got head/valve damage or piston/ring damage.

Other thoughts:

• I rather doubt your chain skipped a tooth given the different compression readings.
• My bet is you have either head or valve damage.
• How many RPMs did you hit immediately after you shifted?

 

hmmm i was doing probably 150km/h and over-revved for sure.