CEL P0300, 301, 302, 303

This morning, I went to top off .5 qt of oil (knew I was a little low from an oil-change a week ago). Started it up drove it out of garage onto driveway, and let it idle to warm while I run in the house to wash hands etc. Then came out and noticed the exhausted sounded weird (like misfiring), and noticed CEL was solid lite. Shut her down, check the oil cap and retighten, and restarted it, CEL still solid lite, but the car idled fine, and no misfire was felt. So I drove it into the office since I realized my Scantool is in the office... So hooked it up and captured the following 4 codes P0300 (misfire) P0301, P0302, P0303 & 5 [pending] codes, not quite sure what pending means from scantool: P0130 P1313 P1314 P1315 P1319 All looks to be from the driver side bank.. What would cause misfire to single bank when cold? Could topping off oil caused this? I was pretty sure the oil cap was tight first time around. I'm very sure Oil is clean, no intermix problems (checked coolant color the other day after changing oil, and dipstick still clean). Car is a 99' 996 that I picked up 1.5 months ago and passed PPI from Squire Automotive. No CEL since purchase, nor any codes during PPI. About to take car for a 3k mile trip to San Diego tomorrow.. I will bring my scan tool and keep monitoring it.. So far after clearing code, car runs good and CEL stayed off.

Chances are you started the car and shut it off too quickly, then restarting caused rich fuel mixture and coresponding misfires. Clearing the code and running the motor should clear it up. Be safe on your Cali trip and call me if anything goes wrong, I will come get you

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First thing that comes to mind is coil packs. A '99 might be on its original coil packs. Topping off with oil not a cause of the errors unless you topped off oil with the engine idling and probably not even then. Not supposed to do this but I've done it a few times and it -- or added an oil additive -- has never caused any error codes let alone misfire error codes. How much oil did you have to add? Was oil a bit low or really really low that could indicate a more serious problem than normal and simple oil consumption? While on the subject of oil, be sure the oil cap is not leaking. My 02 Boxster's original oil cap started leaking and I missed it and replaced a MAF before noticing the cap was leaking while engine at idle. Cost to replace MAF: Several hundred dollars. Cost to replace leaking oil filler cap: Under $20. Another possibility is a camshaft Variocam solenoid has quit working. However, I would expect other error codes related to this hardware and its control circuitry. P1313 to P1318 refer to misfires cyls. 1 to 6, emission related. (P1319 is general misfire emissions related.) The P1313 to P1319 codes differ from P0301 to P036 which are misfires cyls. 1 to 6 damaging to TWC (three way converter). The P13XX misfire codes -- emissions related -- suggest MAF or possibly some fuel supply problem on that side of the engine. When the CEL lights again look at the long term fuel trims and report what they are. With the mention of MAF above, there is another possible cause and one that is well no surprise: MAF. That the engine controller is reporting both TWC damaging misfires and emisions related misfires seems contradictory but could be explained by an erratically operating MAF. Clear the codes. Then drive the car and if the CEL comes on try to note what kind of driving led up to the CEL coming on. Once you have a good feel that you can reproduce the symptom, if the symptom proves to appear consistently, would be to then disconnect the MAF from the engine wiring harness and clear the codes, then drive the can in a similar fashion and see if the CEL comes on (it may cause the MAF disconnected) and if the misfire codes are still present. If they are not... MAF is prime suspect. I do not know the history of the car, but it can't hurt to run a bottle or two of Techron through the gas tank. Follow directions on the bottle. This stuff will remove injector and valve deposits (back of intake valves can develop a build up of deposits that interfere with air/fuel flow into chamber which can lead to improper combustion and misfires) and combustion chamber even O2 sensor and catalytic converter deposits. I like to schedule a treatment of Techron just before a scheduled oil change to remove any additional contamination the Techron and any of the stuff it removes this subjects the engine oil to. Lastly, regarding gasoline: Generally my advice is to be sure you buy a quality gas, run premium, and buy at a busy station so the car gets fresh gas. Sincerely, Macster.

Thanks Ed for offering to come get me and Macster for all the great advice. Glad to update that after 1k miles in (13 straight hours yesterday to bay area, then 6 straight hours today to Irvine), the issue hasn't occurred again. As a matter of fact, car is running in top shape, with long stretches of 100+ along I-5 in mid of Cali.. Man the ROW M030 rides amazing over all types of bumps and undulation.. (side note, after living in WA the last three years, i realized how much i miss cali driving!!) Will keep monitoring CEL and update this thread when necessary. Hope you all had a great Christmas!

oh to answer Macster's questions, i added .5 qt of oil. it's not burning or leaking, i knew when i did my oilchange i was .5 qt short of oil. i havent checked oil yet aftr 1k mile drive, though the electronic gauge after each gas up did not show any difference. And i agree premium quality gas is a must!! thx!

I didn't know these cars would go 100+

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Careful on I-5. There are bears in the air and one county has a "hanging" judge that really rakes speeders over the coals and takes pleasure in doing so. Licenses are lost. Cars are impounded. My experience is that a long drive -- 100+ miles at sustained highway speeds -- goes along way to clearing out the cobwebs. I've noticed this in several of my cars, Boxster, and Turbo and even an 06 GTO that I drove down to Huntington Beach earlier this year. At first fill up down about where I-5 and 99 come together engine was purring. With my Porsches my usual route east takes me over and down 99 to Bakersfield and on to 58 where I usually fill up at station on 58 just east and south of Bakersfield. At this time the engine's feeling so smooth and peppy. Nice. Then the climb up 58 to Tehachapi and then down into Mojave and on over to Barstow is a real pleasure. The long haul -- 140 miles or so -- on I-40 from Barstow to Needles can be a real blast as long as one looks out for the bears on the road and in the air. V1 and CB radio help. Sincerely, Macster.

Ed, a buck and a quarter to be exact... Macster, oh i hear you about the speeding on I5 in mid cali! was travelling along at very fast speeds with 3 other duo-sport enduro bikes, they were really fast 100+ cutting through traffic, then came up to a chp coming on a few exits past Coalinga, i got lucky and slowed right before he got on, but the 3 bikes kept going 85+ despite chp directly behind them. so they cops pulled all three over.. needless to say after that, i didn't go 100+ anymore.. had v1 myself, but a cb will definitely help... great driving directions, where do you go from barstow? LV? and gasing up at 58 is my fav since gas prices is best here.. will keep eyes for bears on the road and in the skys on way back tuesday, though i will be going through Highway 1, so it's gonna be slow, and yea 101 will be taken with caution! cheers, Herb

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The V1 did its job by helping make you more observant you spotted the CHP and slowed down. I spot them much more quickly than I used too and that alone helps. Besides, I also spot other things that just make me a better driver. Paying attention is critical to being a safe and good driver. From Barstow I almost always head east on I-40 towards my final destination back in the mid-west to visit my folks. Once in a great while, but not for several years now, I'd turn up I-15 and stop at LV for the night, but almost always I'm in a hurry to get to my destination and I-40 is the shorter route. I have driven it many times and know the road and the stops, etc., and can make good time. The route up I-15 into AZ -- just a corner -- then into Utah and up to I-70 then east is a nice drive. I-15 heading north into St. George, Utah, is one fine road, scenic even and I-15 on up to I-70 and then I-70 east through CO a nice drive with no snow of course. Avoid in the winter cause a snowstorm can strand you for a day or more. But once out of Denver on I-70.... oh the eternity that KS represents. 400+ miles of, well, Kansas. I've "cheated" a bit and dropped down off of I-70 at Limon, CO and taken state roads east. A bit better then I-70 but bears, county mounties and city kitties everywhere and you have to slow down for every burg and town or else. A few times I've come up I-25 and then shot east out of Pueblo on old 50 highway. Again a bit of the change from I-70 but you have to watch your speed. Porsches stick out like sore thumbs on these byways and any hint of speeding will get you pulled over, by Bubba, the sheriff, who's standard greeting is "You're in a heap of trouble, boy". Sincerely, Macster.

wait you have it ALL backwards.... the higher speeds are for 101.... anyone can go 100 straight be safe and see you back home soon

I will not go over 100mph in the Porsche I will not go over 100mph in the Porsche I will not go over 100mph in the Porsche I will not go over 100mph in the Porsche I will not go over 100mph in the Porsche I will not go over 100mph in the Porsche Works about as good as punishment in school 30 over or 100 gets the vehicle confiscated here. Drive safe and watch out for jack rabbits or plain rabbits.