I know this may be a lost cause but trying to figure some weird issues out with my 2003 cl600. Ive noticed when its warming up it starts to misfire, it only happens when its warming up however. I can turn the car off and back on and it will be gone. The codes are p0300, 301, and 304 for the misfires. I also get a P0153 code even though ive already replaced both upstream o2 sensors, and a p0451 code. I have rebuilt coils and VT from V1ICpack that i got about 4 months ago. Ive also replaced the MAP sensor and have run injector cleaner through it as advised from a local mercedes shop. I can do heavy pulls and it will be just fine but it only seems to happen when warming up. Any possible answers or good places to start?

 

During warm up, more fuel is injected into the engine than when running normally. Have you checked your fuel pressure and checked for vacuum leaks? Also did you use an genuine mass airflow sensor, or an aftermarket one?

 

I used a bosch map sensor. I have replaced some vacuum lines but havent found any leaks. Whats the best way to test fuel pressure?. Another code i forgot to mention. It will sometimes randomly throw a p0455 code as well with the 0451 code.

 

Get access to DAS. These ODB fault codes could mean anything by now.
Only DAS will tell you what's going on with the car.

Is the Mercedes-Benz product number scraped off of the product?

 

Ive been looking into getting a good scanner for this car. Any place to get a good one for relatively cheap? Also the number was not scraped off im pretty sure they were the same part # ill check though to be sure