My 95 SL2 (DOHC, 215k miles) just failed the Harris Co, TX emissions test for the second time, NOx in both cases. After the first failure I replaced the EGR valve, which was pretty dirty and which may have been sticking. I would occasionally get the
32 error code, so the computer thought there was a problem with it also. I also replaced a number of other items: coolant and air temp sensors; plugs; plug wires; valve cover gasket (old one leaked oil into the spark plug wells, no reason to put new plug wires into pools of oil); air filter. Changed coolant; changed oil and filter. Also cleaned out the throttle body and idle air control valve. Also replaced the PCV valve. Second time around it also failed, at least the first part of the test- high rpm on "dynamometer" test, NOx failure as before.
I would appreciate any repair suggestions that will get this thing to pass. Most of the parts I've replaced fall into the "routine maintenance" category, but I don't want to continue down the "try replacing this" trail unless there's a good chance that it'll solve the problem. The blue book value on the car isn't that great, and since I anticipate moving outside the Harris Co. air emission testing zone in several months it'll be a moot point anyway.
TIA.
Bob T.