Welcome to the Australian Ford Forums forum.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and inserts advertising. By joining our free community you will have access to post topics, communicate privately with other members, respond to polls, upload content and access many other special features without post based advertising banners. Registration is simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact us.

Please Note: All new registrations go through a manual approval queue to keep spammers out. This is checked twice each day so there will be a delay before your registration is activated.

Go Back   Australian Ford Forums > Club and Speciality Forums > Forum Community Car Clubs > AU Falcon.com.au

Reply
 
Thread Tools Display Modes
Old 22-08-2012, 12:25 PM   #1
rowan194
FF.Com.Au Hardcore
 
Join Date: Jun 2005
Posts: 588
Default Hesitation/mild surging when applying throttle at cruise speed

A few days ago on the freeway I was cruising at about 80km/hr, put my foot down a fair bit to get into a better position to change lanes, but nothing happened... no change in engine RPM, no trans kickdown. As I released the accel back to the position I had it in, the trans made a clunk as if it had started changing, but aborted when it realised I'd gone back to cruise speed.

Possibly related, the next day I was again already at road speed, behind a slower car, which then cleared, so I put the foot down... this time it did accelerate, but it was a bit sluggish, and I could feel the car wavering, like there was a fat guy rocking back and forth in the seat.

Have not experienced any issues like a misfire or anything noticeable when accelerating normally from standstill, it's just when cruising and I give it extra juice.

Didn't see any leadup to this behaviour, first time was sudden as mentioned above. No probs yesterday. Any ideas?

rowan194 is offline   Reply With Quote Multi-Quote with this Post
Old 22-08-2012, 12:35 PM   #2
Mr Hardware
Flairs - Truckers Delight
 
Mr Hardware's Avatar
 
Join Date: Aug 2006
Location: Brisbane Northside Likes: Opposite Lock
Posts: 5,731
Tech Writer: Recognition for the technical writers of AFF - Issue reason: The excellent how to on LPG jet cleaning. 
Default Re: Hesitation/mild surging when applying throttle at cruise speed

usual questions
how long since you replaced plugs, air filter, fuel filter, did and ISC clean, did a battery reset?
__________________
Current: Silhouette Black 2007 SY Ford Territory TX RWD 7-seater "Black Banger"
2006-2016: Regency Red 2000 AUII Ford Falcon Forte Automatic Sedan Tickford LPG "Millennium Falcon"
Mr Hardware is offline   Reply With Quote Multi-Quote with this Post
Old 22-08-2012, 01:14 PM   #3
robbyj
Rob
 
robbyj's Avatar
 
Join Date: Jan 2010
Location: VN Capital
Posts: 1,584
Default Re: Hesitation/mild surging when applying throttle at cruise speed

sounds like a spark issue, IE what Mr Hardware said. My bet would be plugs and leads.
__________________
99 liquid silver AU Classic -Sold
Supercharged Nissan 350z 280rwkw
Blueprint series 3 AU V8 manual
robbyj is offline   Reply With Quote Multi-Quote with this Post
Old 22-08-2012, 04:42 PM   #4
dieseltrain79
FF.Com.Au Hardcore
 
Join Date: Dec 2009
Posts: 905
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Gearbox slipping if it's not a misfire maybe .
__________________
1998 AU VCT Ghia - Stock as a rock - Wifes car

1991 Toyota Soarer TT - 11.72 @ 116.7mph

2004 Ford Escape XLT V6 - Family Ride .
dieseltrain79 is offline   Reply With Quote Multi-Quote with this Post
Old 22-08-2012, 05:51 PM   #5
SirHenry
Falcon Unbelievable!
 
Join Date: Jul 2005
Location: Uncle Henry's Garage
Posts: 382
Default Re: Hesitation/mild surging when applying throttle at cruise speed

How old is the coil pack?
SirHenry is offline   Reply With Quote Multi-Quote with this Post
Old 23-08-2012, 01:48 PM   #6
rowan194
FF.Com.Au Hardcore
 
Join Date: Jun 2005
Posts: 588
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Coil pack, leads and sparks were replaced about a year/20,000km ago. Air filter would have been done around the same time.

Not sure about the fuel filter, would be at least a couple of years since it has been serviced at a dealer, and I haven't changed it myself since.

I'm going to attack the intake with some carby cleaner today then do an ECU reset and see what happens, but to make things more difficult, the issue hasn't happened again, apart from those 2 (separate) times. Hope it's not the trans, I'm up to 207,000km, so it would be almost geriatric by now...
rowan194 is offline   Reply With Quote Multi-Quote with this Post
Old 23-08-2012, 02:03 PM   #7
Evgeni
Auto Nerd
 
Evgeni's Avatar
 
Join Date: Feb 2012
Location: Sydney
Posts: 808
Valued Contributor: For members whose non technical contributions are worthy of recognition. - Issue reason: In recognition of the many hours spent scanning information for the benefit of AFF members. 
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Worth having a look at the TPS output and seeing if there are any flatspots. Pretty quick check - just need a multimeter and a pin.
Evgeni is offline   Reply With Quote Multi-Quote with this Post
Old 23-08-2012, 03:50 PM   #8
rowan194
FF.Com.Au Hardcore
 
Join Date: Jun 2005
Posts: 588
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Quote:
Originally Posted by Evgeni
Worth having a look at the TPS output and seeing if there are any flatspots. Pretty quick check - just need a multimeter and a pin.
Cheers. Didn't think of that. If the output is a little dodgy it would explain why the trans didn't even thinking about kicking down until the point that I released the accel, maybe it didn't even see me pressing harder for those few seconds... but wouldn't the butterfly being physically further open still do something to the engine revs?
rowan194 is offline   Reply With Quote Multi-Quote with this Post
Old 23-08-2012, 06:27 PM   #9
SirHenry
Falcon Unbelievable!
 
Join Date: Jul 2005
Location: Uncle Henry's Garage
Posts: 382
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Quote:
Originally Posted by rowan194
Coil pack, leads and sparks were replaced about a year/20,000km ago. Air filter would have been done around the same time.

Not sure about the fuel filter, would be at least a couple of years since it has been serviced at a dealer, and I haven't changed it myself since.

I'm going to attack the intake with some carby cleaner today then do an ECU reset and see what happens, but to make things more difficult, the issue hasn't happened again, apart from those 2 (separate) times. Hope it's not the trans, I'm up to 207,000km, so it would be almost geriatric by now...
Nah mine's up to 240k and still going strong, just keep it serviced.

Sounds like good plan of attack
SirHenry is offline   Reply With Quote Multi-Quote with this Post
Old 23-08-2012, 06:53 PM   #10
Evgeni
Auto Nerd
 
Evgeni's Avatar
 
Join Date: Feb 2012
Location: Sydney
Posts: 808
Valued Contributor: For members whose non technical contributions are worthy of recognition. - Issue reason: In recognition of the many hours spent scanning information for the benefit of AFF members. 
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Quote:
Originally Posted by rowan194
Cheers. Didn't think of that. If the output is a little dodgy it would explain why the trans didn't even thinking about kicking down until the point that I released the accel, maybe it didn't even see me pressing harder for those few seconds... but wouldn't the butterfly being physically further open still do something to the engine revs?
Yes, these things can cause a bit of havoc when they play up.
I guess with the butterfly open, you would let more air into the intake. Given the map sensor is in the intake, it would register and it would raise the rpm. Suppose if the TPS was not corresponding to this action, things like the injector pulse, gear selection would not necessarily be able to react to your commands.
Let us know how it goes. Good luck.
Evgeni is offline   Reply With Quote Multi-Quote with this Post
Old 21-10-2020, 04:42 PM   #11
ThosK
Starter Motor
 
Join Date: Sep 2020
Posts: 2
Default Re: Hesitation/mild surging when applying throttle at cruise speed

Hi guys
Had a surging and stalling problem. After new coils plugs etc and heartache I found the problem. There a small L shaped hose going from the air intake to the rocker cover, for cooling of the upper motor I think. The hotter the motor the more the hose sucks out of the air intake . This causes the various sensors to play up.
I diverted the little hose away from the air intake and blocked the hole . The rocker cover was then sucking air in from the engine bay. PROBLEM FIXED
ThosK is offline   Reply With Quote Multi-Quote with this Post
Reply


Forum Jump


All times are GMT +11. The time now is 03:53 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Other than what is legally copyrighted by the respective owners, this site is copyright www.fordforums.com.au
Positive SSL