Boxster basics

[Frodo]

OK, had a question. My car has developed the following symptoms: When driving, especially when first engaging the clutch in first, it seems to stutter or hesitate just a little. I'll also notice it to a lesser extent in higher gears. It is also idling just a little rougher than she used to. These signs are all very subtle---If I’m not paying close attention I sometimes don’t even notice it. On acceleration under anything even close to WOT, it’s totally unnoticeable.

Anybody want to give me a list of rule-outs as to likely causes of this could be? Thanks, in advance.

[Burg Boxster]

Sounds like it's engine (i.e. fuel/combustion) shutter/stutter than mechanical. If mechanical, I'd start by looking at engine mount and asking when clutch was last replaced and/or bled.

For engine though, I'll start by asking if you recently replaced or disconnected the battery? If so, could be simply the DME relearning.

If not, I assume you're not getting a CEL light? If you are, go to local parts store and have them read the code.

Otherwise, I'd start by cleaning the MAF, throttle body and throttle control valve. Also, check your air fliter. By some chance something big may have gotten sucked in and is restricting the flow.

Tell us more symptoms so we can point to better diagnosis

[Frodo]

Sounds like it's engine (i.e. fuel/combustion) shutter/stutter than mechanical. If mechanical, I'd start by looking at engine mount and asking when clutch was last replaced and/or bled.

No, it doesn’t seem to be ‘mechanical’ in the sense of a shudder or vibration. I’ve read through Pedro’s engine mount DIY, and the symptoms he describes don’t really fit what I’m noticing. It’s just more of a mild hesitation or roughness I hear from the engine itself. At lower RPMs, it seems to have a very subtle power loss. Acceleration at anything approaching WOT and it’s not noticeable at all. I’ve never had the clutch replaced, and I doubt the PO did either---the car had 19k miles when I got it, and it’s got about 49k now. I flushed the brakes and clutch lines a couple months ago.

For engine though, I'll start by asking if you recently replaced or disconnected the battery? If so, could be simply the DME relearning.

Haven’t had to replace the battery yet. I disconnected it last winter when I was doing some alternator work; it ran fine afterwards.

If not, I assume you're not getting a CEL light? If you are, go to local parts store and have them read the code.

Nope, no CEL.

Otherwise, I'd start by cleaning the MAF, throttle body and throttle control valve. Also, check your air fliter. By some chance something big may have gotten sucked in and is restricting the flow.

I took out the air filter a few days ago. There was a little bit of stuff that had been sucked up against the outer, foam portion of the filter, but the inner, pleated paper portion really looked pretty clean. I just used the shop vac on the foam part and popped it back in. Regarding the MAF, I don't really know a whole lot about it, but from what I've read on this forum I was wondering if it might be a MAF issue. Unless anyone’s got any other theories, I guess I’ll pull up Pedro’s DIY page on cleaning up the MAF, etc, and get to work.

Thanks.

[JFP in PA]

Also run a large bottle of Techron through it if you have not already done so..........

[Burg Boxster]

one more thing to consider/check - the AOS. Have you or was it ever replaced? Pull the j-tube off the side of the throttle body and see if there is any pooling of oil in it. There should be a film but no pooling in it. Also, while the car is running, try and remove the oil filler cap. If it comes off relatively easily, you should be fine. If you have to fight to get it off, the AOS could be going south. If functioning properly, the car will stumble when you remove the oil filler cap. If it runs better when removed, then you have a problem.

If pooling oil in j-tube, you'll want to change the AOS PRONTO (~ $120 in parts and 2 hrs DIY). Then clean the throttle body.

Let us know what you find and good luck.

[turbo23dog]

X2 on the Techron; also try a bottle of gas drier such as Heet or similar. The ETOH fuels can leave you with H20 in your gas tank.

[Frodo]

The plot thickens. Today, when I got in the car to come home from work, started her up and...flashing CEL. BUT---only lasted maybe 5 seconds tops. Never came back on as I drove home, and we went out to eat (maybe 8 miles round-trip) without it recurring.

Ordinarily, with the flashing CEL I wouldn't have driven it at all. But I recently experienced the short-lived flashing CEL (a few hundred miles ago). Talked with one guy (at an indy shop whose opinions I tend to respect) who told me to go ahead and drive her. I later took the car up to a place called Steinel's Autowerks (a place in NE Ohio that Jake and 'Phil' could tell you a lot about). The code was for a misfire, cylinder 1, and the guy said (based on it having persisted for only a few secs that time as well) that it could have been due to a number of innocuous reasons. He reset it, told me to let him know if it came back, and suggested I run her hard on the trip back, blow things out a bit. I took his advice, and the car has been running well since---no CEL--, until the mild symptoms (running slightly rough, basically) that prompted me to start this thread. And, the brief CEL that occurred today.

I'll try the Techron, etc, but for now I had the following questions:

1) Would any of the possible causes discussed so far be likely to trigger a (brief) flashing CEL?

2) If so, would the fairly straight-forward DIYs recommended here (using Techron, cleaning the throttle body, MAF, etc.) be likely to remedy the situation? I'm just trying to figure out if I should start tinkering or if, on the contrary, the problem is involved enough I should just throw in the towel and take her in somewhere to be checked out professionally.

3) Is driving the car that briefly flashed a CEL a really bad idea? (I've gotten the clear impression from folks I've talked with around here that, with it having lasted only a few secs, it's not likely at all to be a problem.)

Whadaya think??