Hello,

I'm new to the forums and also new to owning an Audi. I have a 1999 Audi A4 Quattro 1.8t. Auto transmission at about 160k miles.

Recently I have been having acceleration/idle issues and have spent hours scouring google and this forum. I'm hoping I'm not just missing a post, but have given up out of frustration and wanting to get this situation fixed soon.

I took my car to AutoZone for a code read, and got back P0422, P0102, and P0303. I went from there to one of the only Audi mechanics in town that I know of (Wichita, KS isn't a big Audi city). He said that I needed to replace my MAF and that would fix the issue.

Now, to catch you up, when idling the RPM gauge bounces slightly. When accelerating, I feel a pretty significant hesitation followed by what feels like just pure lack of power.

Taking the mechanic's advice I first bought some CRC MAF Cleaner and removed the part, cleaned it, then replaced it. I noticed a slight improvement, but wasn't satisfied. So I bought a replacement MAF and installed that. Still not fixing my issue. My next thought is that I need to replace my post-cat o2 sensor.

My purpose in posting this novella (though, non-fictional) is to get some suggestions and hopefully avoid having to replace my catalytic converter completely.

Thanks in advance!

 

First off, clear the codes, and swap coil packs around. Take the #3 coil and swap it with the #4 (P0303 is a cylinder 3 misfire). Run the car and see what codes come up. If you get a P0304 next, it means the misfire moved with the coil and the coil needs replacement. If it stays in cylinder 3, check your plugs and look for vacuum leaks. Any of those codes could result from the misfire itself, do I'd start with that and go from there.

 

P0442 is an EVAP system code, possibly a leaky gas tank cap.
P0102 is MAF sensor code, and you may want to check this link. OBDII Code P0102 AUDI - Mass or Volume Air Flow Circuit Low Input | Engine-Codes.com
P0303 is a #3 cylinder misfire, and follow info on post by 'ImTheDevil"
There is a good possibility that if you fix the misfire, the other codes will clear.

 

He has 0422 though, cat efficiency. A misfire will screw up the exhaust gas mixtures and can be reflected by improper cat efficiency.

 

Good point. Additionally, the misfire can cause the cat to overheat and eventually kill it.

 

Thank you both for the suggestions. I will be working on it today so i'll post back later and let you know what I come back with.

 

Ok, so this is a bit later than I had intended on updating.

Spark plugs did the trick. I had swapped the coil packs from cylinder 3 and 4, still came up with a cylinder 3 misfire. Changed all 4 plugs, runs like a charm.

Thank you guys for your help. I appreciate it.