Ok, so to make this long story short. new engine from mazda 2k miles ago, at 57k now. Under load in first gear i cant get past 6k rpm. Second gear its around 5300 and just gets worse from there in every gear. (MTX) My engine was throwing Po300, Po421, Po303... So i changed the spark plugs. In doing so I found that the retarded mazda tech that broke my grille when it was at mazda also decided that he didnt need to replace one of the coil bolts which was on cylinder number 3. So I put everything back together and I made sure all of the coils were snug on the new spark plugs and that no dirty had gotten on the die-electric grease in the coil boot. Now i have cylinder 2 misfire and I still have no power at higher rpms. I was looking at some other threads and it sounds like my precats might be dead because it sounds like thats what might have killed my engine.... what do you guys think?
Oh also Im getting like 250 miles to the tank when i was getting 400 on the previous engine
Oh also Im getting like 250 miles to the tank when i was getting 400 on the previous engine