JP986

I replaced the two pre-cat oxygen sensors. The car runs perfect now- no gas smell, engine stuttering or black smoke anymore. After 40 miles the engine check light came back on (P0130), I assume it is due to the dirt and carb which is still in the engine. I added some Techron (Chevron) engine cleaner to the fuel and fired the engine with high rpms on the highway to get it hot and clean- seems to work! So far (140miles) the light didn't came back on.

I replaced the two pre-cat oxygen sensors. The car runs perfect now- no gas smell, engine stuttering or black smoke anymore. After 40 miles the engine check light came back on (P0130), I assume it is due to the dirt and carb which is still in the engine. I added some Techron (Chevron) engine cleaner to the fuel and fired the engine with high rpms on the highway to get it hot and clean- seems to work! So far (140miles) the light didn't came back on.

do we have an update? First off, If your going to take it to get fixed, make sure he is a technician not just a parts changer, things can get expensive if its not diagnosed properly. The Tech should first analyze the dme data and look for the tell tale signs of rich or lean condition, for lean condition I would then procede to look for vacuum leak, oil filler cap as Chris said, and If you dont have a smoke machine, use propane around the intake, oil separator ect. and look at the o2 signals for rich reading, high voltage close to .800 1.0 volts. If no leak then most likely it is your Maf. By the way to test an O2 sensor to see if it is Biased Lean all you have to do is create a rich and lean condition and see voltage transitions, usaully with O-scope, transition time should be less than 200 milliseconds. if no transition then you have a dead o2 sensor. The tech should do a hard reset after erasing codes to reset the adaptation values back to 0.00 vizcarra44 are there any updates? I have the same problems and no idea what to do anymore. I already replaced the MAF, oil separator incl. J-Tube, Air- Check valve, but my Boxster is still stuttering and black smoke is coming out of the exhaust at higher rpms and at idle speed. Here are my fault codes: 27 OXS sensing range 1, Cyl 1-3, P1123 or P1124 34 OXS sensing range 2, Cyl 4-6, P1129 or P1130 10 OXS Sensor before cat cyl 1-3, P0130, 0134, 0131, 0132 * 18 OXS Sensor before cat cyl 4-6, P0150, 0154, 0151, 0152 * 26 OXS sensing range 2, cyl 1-3. * 55 Misfire Cyl 6 emission related, P1318 53 Misfire Cyl 4 emission related, P1316 * 54 Misfire Cyl 5 emission related, P1317 * 62 Misfire Cyl 5 emission related, P1319 *

cleaned the MAF today and afterwards cleared the computer. Nothing changed - CEL came back on, engine is stuttering and black smoke comes after 3000rpms. Is there a way to check my O2 sensors? How do I know that my cat is still working?

The codes marked with a * returned. I just checked all my documents and when I had the trouble with my MAF I had similar codes. I will clean my MAF tomorrow- maybe that helps, allthough I don't think so it is just 3 months old and at that time I never had black smoke...

I know- it was not the EGR- they replaced the Air Pump Valve (993.113.250.03). To find another garage here in Michigan is not so easy - most of them have not really experience with the Boxster, so they just start to replace one part after the other... To replace the entire engine would be way cheaper I guess. Here is my "best of" failure codes: 27 OXS sensing range 1, Cyl 1-3, P1123 or P1124 34 OXS sensing range 2, Cyl 4-6, P1129 or P1130 10 OXS Sensor before cat cyl 1-3, P0130, 0134, 0131, 0132 * 18 OXS Sensor before cat cyl 4-6, P0150, 0154, 0151, 0152 * 26 OXS sensing range 2, cyl 1-3. * 55 Misfire Cyl 6 emission related, P1318 53 Misfire Cyl 4 emission related, P1316 * 54 Misfire Cyl 5 emission related, P1317 * 62 Misfire Cyl 5 emission related, P1319 *

A few weeks ago I replaced my Oil separator with the new updated version on my 2.5L Boxster with 90k on it (proud daily driver). I also replaced the J-Tube (thanks to Mike Focke!), but afterwards the car was still running bad - black smoke (especially at higher rpm's) and when I stop to accalerate (driving with constant speed) the engine is stuttering. At my service station they replaced the sort of EGR valve (cut-off valve), cause they thought it is a secondary air problem - it didn't changed a thing. Yesterday I wanted to clean the throttle body and I noticed the new J-Tube from the AOS is full with oil again!!! Does anyone has an idea what's wrong with my car? I still have engine failure codes from all O2 sensors and a lot of missfires on both banks. I think my entire system runs too lean and that's why the engine get's sometimes too much fuel injected (black smoke). I checked the car for secondary air leakages and already replaced the MAF.... 1998 Boxster, 2.5L, 5-Speed, 90.000 miles