Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Boxster General Discussions

Reply
 
LinkBack Thread Tools Display Modes
Old 05-03-2012, 07:15 PM   #1
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
Hesitation at high RPM's

My 98 Boxster seems to hesitate after 5,500 rpm's. It doesn't always do it, but at full throttle it sometimes feels like it stumbles. The air filter is new. I had my indy change the spark plugs. He inspected the coil packs and said they were fine. Any ideas?

tommy583 is offline   Reply With Quote
Old 05-03-2012, 07:18 PM   #2
Registered User
 
Jager's Avatar
 
Join Date: Jul 2010
Location: California
Posts: 1,815
Garage
Quote:
Originally Posted by tommy583 View Post
My 98 Boxster seems to hesitate after 5,500 rpm's. It doesn't always do it, but at full throttle it sometimes feels like it stumbles. The air filter is new. I had my indy change the spark plugs. He inspected the coil packs and said they were fine. Any ideas?
Fuel filter or fuel pump.
__________________
Jäger

300K Mile Club
Jager is offline   Reply With Quote
Old 05-03-2012, 07:38 PM   #3
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
I forgot to add the the fuel filter is new also.
tommy583 is offline   Reply With Quote
Old 05-03-2012, 08:07 PM   #4
Registered User
 
DFW02S's Avatar
 
Join Date: Nov 2010
Location: DFW
Posts: 380
O2 sensors getting tired?
DFW02S is offline   Reply With Quote
Old 05-03-2012, 11:20 PM   #5
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
Well i bought the car last summer. It did the same thing before i put it away for the winter. Since then i have replaced the plugs, air filter, fuel filter, clutch, IMS bearing, flushed break fluid, replaced belt and replaced AOS. If it could be the coil packs, that would seem like an easy fix. The fuel pump seems like a pain. I believe it's in the tank, i hope i'm wrong about that. My Indy has a fair labor rate, but i'd rather try to do more myself before the wife kills me.
tommy583 is offline   Reply With Quote
Old 05-03-2012, 11:35 PM   #6
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Cucamonga CA
Posts: 3,662
Garage
MAF??? My hesitation cleared up after I changed the MAF. At first there was no CEL but as symptoms got worse I got a CEL, and O2 sensor codes that pointed to a bad MAF.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor
Topless is offline   Reply With Quote
Old 05-03-2012, 11:47 PM   #7
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
MAF? Maybe, but so far I have never had a CEL. Then again I have never hooked up a reader just to make sure. But the CEL light does come on when I switch on the the key, just like all the other lights under the gauges. So I would think that it does work and no one has disabled it.
tommy583 is offline   Reply With Quote
Old 05-04-2012, 04:10 AM   #8
Ex Esso kid
 
Join Date: Dec 2005
Location: NY
Posts: 1,605
Did you retrieve any codes? Bad spark can cause the same, maybe one of the coils how old are the plugs? A can of techron couldn't hurt.

Last edited by Ghostrider 310; 05-04-2012 at 04:19 AM.
Ghostrider 310 is offline   Reply With Quote
Old 05-04-2012, 07:58 AM   #9
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Cucamonga CA
Posts: 3,662
Garage
Quote:
Originally Posted by tommy583 View Post
MAF? Maybe, but so far I have never had a CEL. Then again I have never hooked up a reader just to make sure. But the CEL light does come on when I switch on the the key, just like all the other lights under the gauges. So I would think that it does work and no one has disabled it.
That is the first step in diagnosing these cars. Get it hooked up to a scanner and see what is going on.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor
Topless is offline   Reply With Quote
Old 05-04-2012, 02:12 PM   #10
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
The plugs are around a month old. The tech at the shop said that the coils looked fine when he changed the plugs. But one or more of them could have cracks he didn't see i'm sure. I'm thinking that even though i have never had a CEL i should have it hooked up to a scanner. Does it have to be a Durametric or will any professional scanner that a shop would have work?
tommy583 is offline   Reply With Quote
Old 05-06-2012, 04:29 AM   #11
Registered User
 
Join Date: Sep 2011
Location: eastern NC Crystal Coast
Posts: 413
Quote:
Originally Posted by tommy583 View Post
Well i bought the car last summer. It did the same thing before i put it away for the winter. Since then i have replaced the plugs, air filter, fuel filter, clutch, IMS bearing, flushed break fluid, replaced belt and replaced AOS. If it could be the coil packs, that would seem like an easy fix. The fuel pump seems like a pain. I believe it's in the tank, i hope i'm wrong about that. My Indy has a fair labor rate, but i'd rather try to do more myself before the wife kills me.
Changing the fuel pump is not a pain. Just pay attention. After you do it once , You will say how easy it was to do. Good luck !!
milliemax is offline   Reply With Quote
Old 05-06-2012, 08:26 PM   #12
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
I also forgot to mention that I have a chirping sound upon hitting the gas. It happens more when i let out the clutch ( under load ). If i just hit the gas in neutral ( wife helping ) then it's just a quick chirp, instead of a few chirps. I'm thinking after replacing the belt, I'm putting more stress on a pulley or the water pump. Or after searching the threads maybe the tech didn't snug down one of the spark plugs when he replaced them. Could any of this ( Original Post ) loss of power at higher RPM's and Chirping be related?

Last edited by tommy583; 05-07-2012 at 10:45 AM.
tommy583 is offline   Reply With Quote
Old 05-06-2012, 09:11 PM   #13
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Cucamonga CA
Posts: 3,662
Garage
Quote:
Originally Posted by tommy583 View Post
I also forgot to mention that I have a chirping sound upon hitting the gas. It happens more when i let out the clutch ( under load ). If i just hit the gas in neutral ( wife helping ) then it's just a quick chirp, instead of a few chirps. I'm thinking after replacing the belt, I more stress on a pulley or the water pump. Or after searching the threads maybe the tech didn't snug down one of the spark plugs when he replaced them. Could any of this ( Original Post ) loss of power at higher RPM's and Chirping be related?
Yes.
Failing AOS, loose spark plug, and badly worn chain tensioners have been known to make a chirping sound. Your car is a possible candidate for all three.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor
Topless is offline   Reply With Quote
Old 05-07-2012, 10:51 AM   #14
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
Well the AOS was replaced last fall. It didn't make the noise before the belt and plugs were replaced, but it did hesitate from time to time before that. So they probably aren't related now that i think about it. I'm just going to have to hook it up to a scanner and see what the issue really is before i just throw parts at it.
tommy583 is offline   Reply With Quote
Old 05-07-2012, 05:36 PM   #15
Registered User
 
Join Date: Sep 2011
Location: eastern NC Crystal Coast
Posts: 413
Quote:
Originally Posted by tommy583 View Post
Well the AOS was replaced last fall. It didn't make the noise before the belt and plugs were replaced, but it did hesitate from time to time before that. So they probably aren't related now that i think about it. I'm just going to have to hook it up to a scanner and see what the issue really is before i just throw parts at it.
A new fuel pump is one of the best investments you can make for $ 200.00 bucks. Well worth it !!!
milliemax is offline   Reply With Quote
Old 05-07-2012, 09:12 PM   #16
Track rat
 
Topless's Avatar
 
Join Date: Nov 2006
Location: Cucamonga CA
Posts: 3,662
Garage
Quote:
Originally Posted by milliemax View Post
A new fuel pump is one of the best investments you can make for $ 200.00 bucks. Well worth it !!!
Unless the one in the car is still ok. Changing out good parts is never really a good investment. Get a clear diagnosis first. Measure the fuel pressure and if the fuel pressure is low, change the fuel pump. If the fuel pressure is normal, changing out the fuel pump might be fun but it won't solve the hesitation at high rpm.
__________________
2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor

Last edited by Topless; 05-07-2012 at 09:21 PM.
Topless is offline   Reply With Quote
Old 05-07-2012, 09:39 PM   #17
Ex Esso kid
 
Join Date: Dec 2005
Location: NY
Posts: 1,605
Quote:
Originally Posted by Topless View Post
Unless the one in the car is still ok. Changing out good parts is never really a good investment. Get a clear diagnosis first. Measure the fuel pressure and if the fuel pressure is low, change the fuel pump. If the fuel pressure is normal, changing out the fuel pump might be fun but it won't solve the hesitation at high rpm.
+1 I thought by now the codes would be on the thread, why take the circuitousness hard way when you can get some clues as to where to start looking?
Ghostrider 310 is offline   Reply With Quote
Old 05-08-2012, 07:37 AM   #18
Registered User
 
tim986's Avatar
 
Join Date: Sep 2007
Location: australia
Posts: 20
Garage
Send a message via MSN to tim986
will be spark plugs for sure
tim986 is offline   Reply With Quote
Old 05-08-2012, 02:41 PM   #19
98 Arctic silver 986
 
tommy583's Avatar
 
Join Date: Jul 2011
Location: Upstate, NY
Posts: 1,238
Garage
Well the codes are not on the thread yet because I haven't had the chance to take the car to the shop. The check engine light is not on, nor has it ever been on since i've owned the car. I don't think i can just swing by Auto Zone and have them see if there are any codes can i ? It has been pouring rain here the last few days. I hope to get it somewhere to see if there are any codes in the next day or two. Thanks for all the suggestions so far.
tommy583 is offline   Reply With Quote
Old 05-08-2012, 04:03 PM   #20
Registered User
 
Steve Tinker's Avatar
 
Join Date: Dec 2008
Location: Queensland, Australia
Posts: 1,522
Quote:
Originally Posted by tim986 View Post
will be spark plugs for sure
Read the first thread - plugs have already been changed out by his indy.....

__________________
2001 Boxster S (triple black). Sleeping easier with LN Engineering/Flat 6 IMS upgrade, low temp thermostat & underspeed pulley.
2001 MV Agusta F4.
Steve Tinker is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 02:51 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page