Engine Miss Help?

[btracing]

hi all i have a 2001 is 300 that has developed a miss. the miss only occurs from around 3800 to 4800 rpm but it is a constant miss between those rpm anything lower or higher than that the car runs fine? it has around 103000 miles on it. the cel hasn't came on. any help would be appreciated. thanks.

[smooth1]

Which cylinder? Did you check your plugs?

[btracing]

Which cylinder? Did you check your plugs?

[btracing]

I did change the plugs.not sure which cylinder it is as there is no cel or fault codes and it only does it between those rpm?

[smooth1]

Are you running stock? or do you have any mods?

[btracing]

its all stock... i really don't think it could be a cylinder problem. if it was that i would think it would do it all the time?? i'm thinking its gotta be sensor of some kind but i don't have a cel on. so i really don't know??

[smooth1]

I wasn't thinking cylinder, I was thinking maybe fuel injector, maybe gap to large to small on one of the plugs???? Maybe one of the coil wires are bad??? Maybe dirty 02 sensors and IAT/MAF ??? (Not really sure this would be the case, but you may have a combination of any of these, which could be the causes.)

Do you have an ODB II scanner?

[btracing]

i finally got a cel on scanned it with a OBD2 there is 3 codes in it p0440 p0441 p0446. any ideas? thanks in advance. brandon

[smooth1]

i finally got a cel on scanned it with a OBD2 there is 3 codes in it p0440 p0441 p0446. any ideas? thanks in advance. brandon

Hmm, those are emmissions codes. If I remember right, those usually lead to the gas cap, or ventalation canister for the fuel tank. Try removong your gas cap, then put your cap on the opening, trun it counter clockwise until you feel the lowest point, then turn it clock wise until it clicks 3 or 4 times. See if that takes care of the cel.

[U235a4]

I have the same problem with my 01 is300 it started around 35-45k miles but I now have 70k. my miss hits around 4000 till about 5000 and it's like a wall aka rev limiter and once its past this point it good. no mil light, good milage, shifts good I'm thinking wires or coils but it could be something else I just hate to take this to a garage and get screwed when it's something I could fix if I knew what it was. Also I want to add I notice it misses worse on dry days aka like static discharge and seems better on humid days altho still misses. I thought fuel also but since it seems to pull good from 5k to 6k I can't seem to think it would be a fuel issue aka injectors or pressure.