loss of power during hard acceleration Boxster 986

[YRD]

I have a 2001 Porsche Boxster 2.7.

During hard acceleration I am intermittently losing power for a split second before it kicks in again. This is noticeable when the revs are getting high and the power cuts then jerks forward when the power kicks in again.

Forums seem to point to the MAF sensor for similar problems. I have only just bought the car and documents show the MAF sensor was only replaced one year ago.

Anyone experienced the same or have any ideas what the cause may be?

Edited by YRD on Saturday 6th June 21:47

[Rockster]

YRD said:

I have a 2001 Porsche Boxster 2.7.

During hard acceleration I am intermittently losing power for a split second before it kicks in again. This is noticeable when the revs are getting high and the power cuts then jerks forward when the power kicks in again.

Forums seem to point to the MAF sensor for similar problems. I have only just bought the car and documents show the MAF sensor was only replaced one year ago.

Anyone experienced the same or have any ideas what the cause may be?

Edited by YRD on Saturday 6th June 21:47

Since the car is I assume an unknown to you -- unless you obtained full service history -- there could be a couple of explanations.

I take it the CEL (check engine light) is not coming on concurrent with the loss of power? And it is not on solid at any time?

Are you sure you are not hitting the rev limiter? The 2.7l engine can gain RPMs rather quickly in 1st gear and even though it has a 7200 RPM red line you might be bumping up against that.

A true loss of power at high RPMs with no CEL could be in no particular order a fuel supply problem, possibly a fuel filter, an engine intake filter -- it would have to have horribly dirty but who knows when it was last changed, if it was ever changed by the previous owner (assuming you have no real documentation on the car's service history), a spark plug problem, or a coil problem, or a fuel injector problem.

If I had to pick one of the above, I kind of like plugs. They don't have to be bad enough to trigger misfires and a CEL but they can be bad enough to not light off the mixture at high engine speeds.

The "new" MAF also comes under suspicion. New doesn't meant the unit is working properly. There is the question of the MAF being the right one or being of the necessary quality. Some owners seek out the cheapest MAF (or other part) they can find thinking that all MAFs are created equal. Sometimes this proves to not be the case.

There is a MAF test, of sorts. First be very careful. If you static discharge into the MAF connector or the engine harness connector you can ruin a perfectly good MAF or a perfectly good and very expensive DME.

Anyhow, carefully at the wiring harness disconnect the MAF. Using an OBD2 code reader clear the error codes. Even if there are no active codes this resets all the fuel trims to their defaults. Then just drive the car around normally.

The CEL might come on but this is due to the MAF being unplugged. You can read the code to confirm this. If it the code points to something else you are done. Get the car flat bedded to a shop for a pro tech's attention.

Once the engine is up to full operating temp and you are comfortable with the way the engine is behaving then see if the behavior at high RPM appears.

If if does then the source of the symptom is not the MAF. It it does not appear then back home reconnect the MAF and clear the codes again and road test the vehicle. If the symptom returns...well, there you are: MAF.

What fuel are you using? I hope a proper octane grade of fuel and a name brand and you are buying this fuel from a busy station to ensure you get fresh fuel.

Absent a check engine light or absent any pending OBD2 error codes that could provide some hint as to what might be going on it can be difficult to determine what is going on. Either you pay for some Porsche expert's diagnostics time or you pay to throw parts at the behavior and then generally when that fails you pay for the diagnosis anyhow.