Purchased used 2003 S-type two years ago. Previous owner replaced the stock air intake system with a "performance" air intake, like the kind you can get from Advance Auto, you know, pipe with Spectre air filter on the end.

I've been getting codes P0172/P0175 (too rich) along with periodic Restricted Performance. The RP seems to only occur when driving in traffic or if I let it idle for a while. It clears up when I drive continuously and at speeds greater than city traffic.

I've replaced the MAF sensor twice since I purchased the vehicle, most recently within the last month. Doesn't seem to help.

Does anyone have any suggestions as to what/how to troubleshoot next, preferably starting with the least-cost options? Is the "performance" air intake the problem? Anyone have any experience with these?

Thanks.

 

According to the codes:

-Restricted air filter

-Leaking fuel injector(s)

-Oil contaminated fuel, to many cold starts with engine not coming up to running temperture

- MAF sensor

Says to start engine, bring to operating temp., let idle 10 minutes.

 

I'd get a stock system cheap from a wrecker and fit it. Problem will likely be fixed. Most of these aftermarket ones suck hot air from the engine bay and/or have an air leak. Both are bad.

 

Another total waste of money the aftermarket brings to the table.

 

Ditto. tklarner, your aftermarket open airfilter isn't compatible with the fuel metering. We've seen the exact presentation with this set up. Toss it in favor of stock air box plus K&N flat panel air filter.

 

Thanks for all of your help. I will try getting a used stock intake system. Hopefully will solve the issue.

 

My mechanic installed a "new" (junkyard) stock air intake system, and it solved the problem. Thank you for all of your help.

 

Hooray! Thanks for posting a follow-up.

 

Rock On to TKlarner!