Rough idle, maybe missing


I have a 2003 Ford Explorer sport. check engine light was on, pulled code and found the pcv hose was split. Replaced hose and plugs, no check engine light. I washed my air filter, it was a bit damp when I put it back, now the truck has a rough idle, seems likes it’s missing sometimes. Could this be from the air filter being damp? Nothing else was changed or replaced. Thank you


[b]Installing the damp filter probably sent whatever you used to wash the filter with into the Mass Air Flow sensor. The MAF sensor is a very sensitive component and can’t tolerate any type of contamination. As this is one of the main inputs into the ECU. So the MAF sensor isn’t able to measure the proper amount air that’s entering the engine.

About all you can do at this point is purchase an aerosol can of MAF sensor cleaner, and try cleaning the MAF sensor. And hope cleaning it restores it’s ability to measure the mass air flow entering the engine.



You WASHED your air filter? You are supposed to buy a new one and toss the old one in the trash. You might be just suffering from a plugged air filter. I don’t know if they respond well to Baptism by immersion and then drying. It might make the pores close up.


Both guys ahead of me have good suggestions. If it’s a regular paper air filter, you replace them, not wash them. If it’s a higher-performance sponge type filter then you can wash those but follow the manufacturers instructions.

It’s not a good idea to re-install the filter in a wet condition. It’s not good for the MAS sensor as mentioned and it may not allow proper air flow into the engine. Cars like dry air filters.