Erratic idle, help
 

Gents can anyone advise what would be the cause of an erratic idle on my 2002 Boxster? Its not bad enough that the car stalls but is quite noticeable.:confused:

Could be lots of things, I would check the engine for vacuum leaks (perhaps a vacuume hose came loose), check the air cleaner, and clean the MAF sensor, for starters. A dirty MAF sensor is a very likely candidate.

Not much activity on this forum, sometimes it can take a while for someone to respond.

Thanks Dave, going to start that today.

Dave, you advised to clean the maf sensor, with air, chemical, can you advise? thanks

Buy some MAF cleaner at your parts house.

You also probably need a special "security" allen wrench to remove the sensor from the air intake. I bought a set security bits from harbor freight for $3 or so.

Here is a link that should help.
http://mike.focke.googlepages.com/checkenginelightcausedbymassairflowsensor

Good luck !

This is perfect, thanks again.

I removed the KN filter and cleaned it as advised with its kit, I then removed the MAF, spray it several times with MAF cleaner, let it dry and installed it. The vehicle definitly has more throttle and speed then before but the idle is still somewhat unsteady, it flucuates between 8K and 650. No signs of a vacuum leak only a small hiss sound for a second on acceleration. Can you advised any further? Thanks

use OEM filters the K&N don't mix well with the MAF's

When is the idle unstable? Cold or Hot or both?

What you should do is check for air leaks or leaky injectors by the TRA'a or RKAT's depending on the year. These are the short term fuel trims and a negative number would be that it is trimming fuel while a positive is that it is adding fuel.

As an example, an intake leak would show as a Positive number being that it is adding fuel to compensate for a leak.

Leaky injectors or to high a fuel pressure would be the opposite.



Best Regards,
Scott Slauson