Question about 2004 Ford Explorer
There are many variables here you didnt supply: did it run perfectly BEFORE the air filter replacement? Did you check the rubber accordion tub from the air filter case to the engine to make sure no hoses or connectors that attatch to the tube may have come loose or fallen out? is the tube TIGHT? Is this an ORIGINAL air filter and air cleaner?
A maf sensor senses airflow, and fuel is balanced to what it reports to the ECM. Your air filter is ahead of the maf. If the filter is restricted, it would cause a misreport and the engine may not run properly or at all. If you have any leaks between the sensor and the engine, misreport...same problem. Sensor gets DIRTY from crud sticking to the hotwires...misreport, mislearn of several key data points (including altitude/baro) and engine may not run.
At this point, without more data...Id verify that tube is tight and no hoses or connections have accidentally come loose. Id check to make sure the air filter you are using is correct for the car (No...any generic K & N doesnt count! Get one of sufficient size. if its some midget chrome thing, that could create a problem). Too big usually wont be a problem, too small will be, though usually restrictions to flow show up most under load and cruise, and car is OK at idle.
Once all that is done, clean the MAF as suggested. However I do not suggest compressed air. The reason they get dirty is becauset hey are heated to 400 degrees to do their job. dust and moisture from the air hits that and should disintegrate, but if its really dirty it liquifies and turns to goop/paste and sticks to them like tar. Air wont necessarily remove that. Further, these are 26g wires that are weight soldered to a steel post. Their connection is NOT durable or designed to withstand ANY pressure or force sincet hey were designed to measure air (nearly weightless and no physical pressure!)! Use carburetor or throttle body cleaner in a spray can, or brake cleaner if thats all you have. aim it at the wires and spray full force from the can onto the maf hotwires for a few seconds, try to get front and rear and spray till the wires are clean and silver (doesnt take much, 2 or 3 seconds is usually enough). when done, dont dry it, it will self dry. You can also use a soft bristled toothbrush on particularly dirty ones, however the wires do break EASILY when physically contacted so be extra gentle and barely touch them if you must at all.
Now heres the key, if your old air filter was filthy, and your maf got dirty because of that...the engine LEARNS airflow and air pressure and remembers it. You have to clear that memory or even though youve cleaned it, it wont reset till many miles are driven and will run badly until then. Disconnect the battery for 30 minutes, turn the key on with the battery disconnected and step on the brake pedal for 10 seconds (to drain out the last of the computers reserve power). remove key, reconnect battery. Now the memory should be erased and baro memory on an 04 should reset to sea level plus 1500 feet (about 150hz when scanned) which should be drivable and smooth enough to startup in most areas except denver. seal level should be 159 hz, denver should be 145ish, it varies by altitude, the car will learn on its own over time, usually at wide open throttle or repeated startups.
Hope it helps.
Posted on Oct 03, 2009
Testimonial: "you were dead on, i cleaned maf sensor and cleared pcm...running great....thanks for the help "
Check the maf sensor for dirt or debrie to gain acces to the maf sensor you will have to unscrew it from the filter box and when you have taken it off just cleanet whith compresed air
Posted on Oct 03, 2009
Doesnt make sense, did you try another filter,make sure all connection and vaccum hose are good,were there any problems before you changed filter?
Posted on Oct 03, 2009
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Posted on Jan 02, 2017
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