Hesitation under WOT in First & Second

[G's02Boxter]

I just picked up an 02 Boxter with 61k. Dealer wanted $1500 for major service so I called Pelican ordered Major Maintenance kit for $100 and spend entire weekend installing everything. I changed out plugs, air, cabin and oil filters. On my way up from driving the car from MIA to ATL I noticed hesitation in the throttle I would say above 3K in first and second. I don't think I noticed the throttle hesitation in 3rd or 4th. and when the car got it only some times would idle surge.

While I was doing the major maintenance I decided to clean my MAF and Throttle Body to see if I could get rid of the hesitation both MAF and Throttle Body were very dirty so I know this helped as my idle has improved it's not fluctuating like it did when the car got hot. However all of the mentioned maintenance things did not solve my hesitation issues. The car with out a doubt runs better, at least idle stays put and is rock solid but I can still feel a slight hesitation winding it out above 3K. Anyone have this and what did you do to fix it? I was thinking injectors need cleaning. Should I try after market fuel injector cleaner? I was always told not to use those products as they typically do more harm than good.

[harryrcb]

could be as simple as a vacuum line fell off. there are several under the intake planum that can easily come off but most likely would screw with your idle or surge. I believe you said you had that under control. Could be a weak fuel pump or the injectors as you indicated. the only way to tell is get fuel pressure and flow readings, unless you have those tools you will need to take it to a shop that does. If you have the means to remove the injectors you can get them checked and cleaned on a flow bench and they will install new filters in the injectors (fine screens to keep particles from jamming the injector open)

[G's02Boxter]

Originally Posted by harryrcb

could be as simple as a vacuum line fell off. there are several under the intake planum that can easily come off but most likely would screw with your idle or surge. I believe you said you had that under control. Could be a weak fuel pump or the injectors as you indicated. the only way to tell is get fuel pressure and flow readings, unless you have those tools you will need to take it to a shop that does. If you have the means to remove the injectors you can get them checked and cleaned on a flow bench and they will install new filters in the injectors (fine screens to keep particles from jamming the injector open)

I checked the vacume lines at least the ones I had access too. There is one that goes right into the intake plenum and I put that back in. I'm wondering if becuase I've changed plugs, cleaned MAF and Throttle Body if the system has to go through some learning curve or reprogram it self all over. It does seem to be running better the more I drive it.

[thstone]

Originally Posted by G's02Boxter

I checked the vacume lines at least the ones I had access too. There is one that goes right into the intake plenum and I put that back in. I'm wondering if becuase I've changed plugs, cleaned MAF and Throttle Body if the system has to go through some learning curve or reprogram it self all over. It does seem to be running better the more I drive it.

If this is the issue, then adaptation will usually take about 20-50 miles of varied driving to take effect.