have recently had the plugs replaced in 04 maxima se. since replacement have started to hear a high pitch squeel under load between 2500 and 3000 rpms. have checked all gasket seals and they are still good. am also getting an influx in rpms while driving, mostly in 2nd gear (seems to go out of gear rev up to between 4-5k rpms and then drops back down and goes back to normal). check engin light came on with a 0507 code. any idea what it could be and what to replace

 

I guess the plug didn't match to your 04 maxima se, it should work perfectly if that matches perfectly... my friend got the same problem and did the same but work perfectly.

 

I have a 94 Accord. I did an engine swap from japan. The engine runs great everything is good except for the fact that the throttle is very tight. I feel like I really have to push down and use leg muscle to give it gas.