Missing on acceleration wile motor is cold???
 

My 99 Boxster is missing after first starting the car wile its still cold. If I let the car warm up it does fine... unless I just jump in it and take off. Then it never stops skipping even after it warms up. There are 2 codes on the car right now p1128 and p1130 but I don't know what those codes mean? And the other morning i didn't have time to let it warm up and started going down the road and the check engine light started flashing but went back to a steady glow... I don't have a clue. So far all I have tried is replacing the air filter. I just ordered a fuel filter but it hasn't come in yet. Any suggestions? :barf:

Join RennTech.org, they have a section for looking up OBD II codes.
According to them, you have oxygen sensor problems.

Clean your MAF, throttle body assembly, plenty of posts regarding both. I had both codes. In addition, I had to replace one of the two rubber boots behind the throttle body due to a razor size slit down the middle. This slit was causing a chasing idle and possibly one or both of these codes. All O2 sensors were replaced as well, codes reappeared afterwards so not sure that helped. Good Luck!

Follow-up, Flashing CEL could shortly mean "Change Engine Light" have you car checked out by a reputable mechanic.

Well, lets start with the simple stuff:

What was the last bit of work you had done on your car, and how long ago was it?
When was the last time you had the spar plugs changed?
Skipping upon starting usually points me in the direction of spark plugs, and ignition coil sticks. Its easy for you to get under the car, and check to see if one of your ignition coil sticks is not snapped onto the spark plug properly.

A quick search on this forum would have let you know that those are codes that involve the computer not being able to adjust the mixture enough for each bank of cylinders. You should try out the search feature, it gives great results for items like that. :)

A flashing check engine light typically means that there is something wrong with the engine, and that damage can be done if you keep driving it while it is flashing. Typically, this means that the catalytic convertors are having too much fuel dumped into them, which sounds logical if your car is misfiring, and spitting raw gasoline into the exhaust system.

Fuel filter and air filter are not going to be the solutions to your issue.
I would start with inspecting the spark plugs and ignition coil sticks first, then move onto the MAF sensor.

If you were here in CO, I would offer to pop by your place with my car and Durametric system, and we could swap my MAF sensor in to see if that resolves the issue after we tried some other stuff. Maybe someone else would be willing to do the same if they live nearby and have a 97 to 99 model?

BC.

Wouldn't it be nice if the car manufacturers provided a light that tells you when it actually was time to change the engine? That would have saved so many people from having major engine failures, don't you think? All those people who suffered IMS failures would have at least had a bit of warning, too.

Nope, the light is a Check Engine light, not a Change Engine light, though we should have Porsche rig something like that up for a future model!

BC.

Thanks!
 

Thanks for all the help guys! Yea it too bad that i live down here in po-dunk Alabama :chicken: because i could use all the help i can get! I dont know very much about my porsche and i cant seem to find a haynes manual on it anywhere! lol :cheers:

This is the manual you want: http://www.amazon.com/Porsche-Boxster-Service-Manual-1997-2004/dp/0837613337/ref=sr_1_1?ie=UTF8&s=books&qid=1258499600&sr=8-1

Been there, done that.

It is your oxygen sensors my friend.

Change them and I'm 99% confident it will fix the problem.

If not, start to look at MAFS and coil packs etc.

Also, and for the benefit of everyone else here, I will share a tidbit of bad advice I received from searching on another forum. Someone suggested unplugging the MAFS to see if this prevented the car throwing up codes, and if so, it is the MAFS which is faulty. BAD IDEA. I unplugged it, car ran just fine but very down on power. When I replaced it with a new MAFS $500 later, the codes came back after 5 minutes. So all I could deduce from that is the car just does not throw up codes if something is unplugged, whether the component works or not.

Good luck!

O2 sensor
 

Well. I guess that would lead me to my next series of questions. How many o2 sensors does the car have? where are they located? Is there anyway to test if there good or not? If I do need to replace them is there any certan type I should get? Thanks for all the help btw y'all have been great! :D

The orange light suggests and your engine is enviromently no running right this is usualy picked up by the oxygen sensor. An engine misfire when cold can be coolant temp sensor telling the ecu it is colder than it realy is causing over fueling, Spark will fail at the plug under cold conditions if the conection between the ciol and the plug is not sound look for carbon tracking down the porcilane on the plug.Trouble codes and engine spark/timming are not related, the ecu has no control over it. Ask your dealer to plug his diognostic tool into your car cheaper in the long run than just changing parts till you find a problem. Just rember this tool only checks ecu operated components no spark related.So it will check engine check light and trouble codes an point you in the direction but it cant tell you weather its say the coolant sensor or the wiring but thats where experiance and dealership back up save you time and money.

Read this about testing your MAF:

http://sites.google.com/site/mikefocke2/checkenginelightcausedbymassairflowsensor

and this about changing your O2 sensors:

http://sites.google.com/site/mikefocke2/oxygensensors

If you go for replacement O2 sensors think seriously about getting ones with the factory type connectors that are simple plug-and-play. With a little research you can get them for around $100 apiece, which is what I paid. You'll read more than a few posts here from people who got univeral sensors for as little as $30 apiece, but there are a lot of potential problems. Using these isn't as simple as soldering on the factory connectors. Trying to save $ by going this route is penny wise, pound foolish IMO, but it's your car and your money.

Let us know how this turns out.

I have the same cold start issue. No CEL. I'm guessing plugs, O2's, or temp sensor. Mine has 55k miles so I'm due for plugs anyway.

Question: Can you have a bad O2 sensor and not trip the CEL? Thanks!

I have been hanging around here for a while and I want to make a few comments.

Troubleshooting problems is a science, it can be an art but it is not alchemy.

ODBII error codes are simple, direct and easily interpreted. THat is why we have them. They do one thing and one thing only, they give you data on faults for the fuel injection system (EFI).

Sometimes the ODBII codes will tell you exactly where to look for the problem. Example: Misfire on cylinder 5.

Some codes are more general and can be caused by a number of things. Example: I had a V8 throwing Lambda (O2)sensor codes and it was due to a leaking head gasket enriching the amount of oxygen in the exhaust mixture beyond the parameter stored in the ECU.

For starters I would suggest that if you want to solve problems on your vehicle that you go to a local parts house and spend $129 for a decent code reader. Mine tells me in simple language what the code means instead of only listing a fault code number.

Second, get a book on basic fuel injection systems and read it. It is not really complicated when you understand how the coolant temp sensor, MAF, fuel maps, O2 sensors and other bits interact.

The third suggestion is that problems in the trouble shooting process are usually due to a mistake in the basic set of assumptions that one enters into the process with. If trouble shooting does not yield the answer then look at what you are assuming to be ok and correct.

I had some buddies put a zip tie on the rear prop shaft of a truck I was doing an intake manifold job on. It took me less than 60 seconds to locate the noise and see that I was the butt of the joke.

Internet forums are helpful for problem solving with two caveats.

One: small simple problems are usually extrapolated to the most exotic cause becuase smart people want to show how much they know. Example: Intermittent miss in V8 was thought by another forum to be exotic valve sticking due to carbon build up due to faulty factoru design, turned out to be a bad plug wire.

Two: The spaggheti against the wall technique is rampant. Forum users will suggest everything remotely related to the system in order to guess what the problem really is and get to beat their chest.

In direct response to your problem.

First: look up the codes.

Second: Design tests to isolate the potential problem and test is it solves the issue.

Third: Fix the problem or examine your "givens" and start over.

Just buying parts and throwing them at the problem is expensive and has the potential to add additional variables to the trouble shooting that can obscure the thing that is causing the codes in the first place.

One of the most difficult for me was a leaking intake manifold on a V8. I replaced it and after went to start the vehicle. No start. Trouble shoot starter and no love. Replace starter, no love. Eventually after re-examining the givens, and much head scratching, I determined that in a completely unrelated problem, the power steering pump had locked up at or near the moment I shut off the truck to do the work and the motor could not turn fast enough in that state to start. Replaced power steering pump and life was good again.

Trouble shooting is a rewarding experience when approached properly. Don't just throw money at the problem.

Thank you for listening and carry on.