Please help with obc codes I own a 1997 M3/4 5 speed it has only 46,000 miles on it and my check engine light came on. used my Peake code reader and codes E3 and E4 showed up book says Oxy sensor adaption limit Cyl#1-3 and Oxysensor adaption limit Cyl# 4-6. Any help would be great Thanks

An intake leak or contaminated MAF would be the most likely causes at that mileage. If the car has an oiled air filter the chances of a problem with the MAF are pretty good. Otherwise the MAF is probably ok and an intake leak is the probable cause.

I do have a oiled CAI I cleaned maf sensor with CRC maf cleaner reset check engine light. The light came back on about 500 miles later. Have not oiled filter lately. Thanks

MAF cleaner will only remove oil that is still soluble. Oil that's polymerized or carbonized on the thin film sensor can't be cleaned off. That said, make sure that you don't have an intake leak before going for a replacement MAF. A smoke test of the intake is the definitive test for leaks associated with the intake manifold, but it won't find leaks at the dipstick, oil filler cap, CCV, or brake booster. Those have to be checked separately. A crankcase pressure check will tell if the CCV has failed and a vacuum test of the booster will tell if it is leaking.

please explain CCV. Again thanks for all your help

CCV == CrankCase Vent and since you have a 97, which is OBD II, you should have one. It is basically a fancy version of a PCV. A failure of it's internal diaphram or one of its hoses is in effect an intake leak.