• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

99 Mustang GT High Rev On Cold Start

  • Thread starter Thread starter OneSick99GT
  • Start date Start date Nov 20, 2018
  • Tags Tags
    high rev idle issues idle surge mustang
Prev
  • 1
  • 2
First Prev 2 of 2

OneSick99GT

Active Member
Nov 20, 2018
364
46
38
Dayton, Ohio
Nov 27, 2018
#21
  • Nov 27, 2018
  • #21
And I will have my ForScan ODB2 scanner w ELM327 USB tomorrow. I'll download the software from forscan website. When I do what should I be looking for. What perimeters do I need to add to the selected PID's. I'm on the website familiarizing myself with the software as to be somewhat knowledgeable on what to do.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Nov 27, 2018
#22
  • Nov 27, 2018
  • #22
I'm asking about an after market alarm system. Why? Because the Ford factory PATS alarm system will NEVER shut off the the motor once it has started. Therefore the start and immediate quitting would not be a symptom of the Ford factory PATS. But start/quitting could be a sign of an AFTER MARKET alarm system.

As for what "could" cause a motor to jump time how about worn timing chain tensioners? Allowing the chains to go slack. The rest is history especially if the motor ever backfires and turns over back wards. Does the motor make a chain rattling noise after a cold start up?
 

OneSick99GT

Active Member
Nov 20, 2018
364
46
38
Dayton, Ohio
Nov 27, 2018
#23
  • Nov 27, 2018
  • #23
I don't think so. I'll inspect the chain tensioners this Thursday. I'll take a video as well. I plan on replacing the fuel filter, crankshaft sensor, pulling each spark plug, checking gap and replacing if necessary and checking the fuel pressure. I'll have to look real good to see if there is an aftermarket alarm installed but I won't know for sure where to look for it. I'm just starting out learning about everything there is to know about my 99 GT. I'll need to know everything for future builds. Plus I'll be using the software you told me to buy.
 

OneSick99GT

Active Member
Nov 20, 2018
364
46
38
Dayton, Ohio
Nov 28, 2018
#24
  • Nov 28, 2018
  • #24
What should I be looking for with the software you told me to buy.
 

OneSick99GT

Active Member
Nov 20, 2018
364
46
38
Dayton, Ohio
Nov 29, 2018
#25
  • Nov 29, 2018
  • #25
WMBURNS,
Attached are some of the files I ran during diagnostics on my mustang with the software you requested I buy. Let me know what you think might be the issue.
 

Attachments

  • Dashboard forscan running data.webp
    44.2 KB · Views: 316
  • Live Data Mustang.webp
    60.3 KB · Views: 279
  • Mustang Error Codes 2.webp
    32.6 KB · Views: 396
  • Mustang Error Codes.webp
    64.4 KB · Views: 277
  • Mustang Graph Data.webp
    46.8 KB · Views: 285

OneSick99GT

Active Member
Nov 20, 2018
364
46
38
Dayton, Ohio
Nov 29, 2018
#26
  • Nov 29, 2018
  • #26
Wouldn't let me attach on previous message. This probabaly isn't important but I thought I would share anyways.
 

Attachments

  • Mustang Modules.webp
    30.8 KB · Views: 284
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

A
Rough idle - cylinder 1 and 6 misfire HELP
  • austindavies935
  • Jul 24, 2025
  • SN95 4.6L Mustang Tech
Replies
12
Views
725
SN95 4.6L Mustang Tech Jul 24, 2025
gkomo
G
Idle surging after warm up
  • GALLY3309
  • Jun 10, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
1
Views
127
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 10, 2026
Noobz347
7
Engine Random hanging idle
  • 706 Saleen
  • Feb 11, 2026
  • Fox 5.0 Mustang Tech
Replies
9
Views
648
Fox 5.0 Mustang Tech Feb 19, 2026
86HO5.0
8
K
2003 GT High Idle, vac leak process
  • krysber
  • May 11, 2025
  • SN95 4.6L Mustang Tech
Replies
2
Views
473
SN95 4.6L Mustang Tech May 11, 2025
krysber
K
F
Engine 1988 Foxbody idle issues
  • fernandosgarage55
  • Apr 28, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
26
Views
621
Fox 5.0 Mustang Tech Apr 30, 2026
AeroCoupe
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?