MAF Code, erratic idle, and trouble starting...

[97ss10]

I just got back from a long trip (2500 miles) and during that trip, I was having some problems. Before leaving I installed a K&N filter, not sure if that has anything to do with it though. The check engine light came on so I stopped at the nearest parts store to get it scanned. It came up with a MAF code so I bought some cleaner and had them clear the code, in hopes that it would solve the problem. After spraying the cleaner in the MAF, I had trouble starting the car and assumed it was because the cleaner hasn't fully evaporated. So I waited about 5 minutes and it eventually started and ran fine with no code. Two or three days later, the light came back on with the same problem so I got it cleared again and hasn't come on since. Another symptom is, when I would start the car, sometimes it would just die immediately but start right back after attempting to start again. Yet another symptom, when I would get to my destination and put it in park, it would idle erratically. It would go from idle to around 1200-1500 RPM then drop back down and sort of surge then it would stop. It seems more like a TPS to me but the car is saying MAF. Any thoughts? Thanks a lot!

[BOPOH]

sounds like vacum problem that is related to K&N oiled filter. is your car TIP? do this: press on brakes really hard before you start car and if dies first time, its something with vacum system. I had samething. Rough idle like yours sounds like MAF issue. K&N are not the best due to oil, never happend to me but i read alot about it.

[Mike@Startup]

first off, remove the MAF when you clean it. Also make sure the car is OFF. If you do it with the car running, it can destroy the MAF.

Everything sounds like a failing MAF. One way to test is just remove the MAF cable & drive as normal. If it runs better, it's the MAF, if it still runs like poop, check for boost leaks. Just realized we are not in the B5 S4 section. Your car may not run well with the MAF disconnected. The B5 S4 runs in MAP mode when the MAF is disconnected. So, I would just try it first when you start it & not drive it that way.

On the filter, take a few paper towels, & blot the filter, to get all the extra oil from it.

[B6Lovin]

^our cars do the same thing mike, if nothing else he may not notice any decrease in performance.

basically when you unplug the MAF you are looking to see whether things get better or stay the same - if they do, your MAF is probably bad. if things get worse then you should start looking for boost leaks, although it sounds like the oil from the filter soaked your sensor and no amount of cleaning can bring back a dying MAF (unfortunately)

do you have a friend with a 1.8T? you can try swapping MAF's with them to see if that fixes your problems too.

[dougyfresh]

although it sounds like the oil from the filter soaked your sensor and no amount of cleaning can bring back a dying MAF (unfortunately)

Very common with having a K&N in a MAF-equipped vehicle.

Ditch the K&N and get a good dry filter. ITGs are good.

[97ss10]

I do have a TIP but I also have one of those damn 3.0's so it definitely has nothing to do with the turbo. :) It didn't really run "bad" when it was doing it, except when it would die on start but then start right back, and the crazy idle when I got to my destination. During the trip it ran fine with the exception of the light coming on. Another thing is that it doesn't do it all the time which makes it a pain in the ass to diagnose. I drove it today and it ran fine, no problems, no lights, and no idling problems.

[Charlescrs6]

have a similar problem... My car is shakey at idle, always starts right away though. The other day i was driving and the check engine light came on, about 3 minutes later i pulled into my destination checked oil and it was low, I put a quart in but the check engine light was still on. Two days later, (yesterday) i was out to breakfast, started up the car (it was hard to turn the key) and the light was off! I was happy but still worried. Today i was driving and the light went on again. Car was shakey at idle before light even came on. Anyone have an Idea? car is a 2003 A4 3.0