while driving rpm's drop engine stumbles then dies, 1992 Mustang 5.0 - Ford Mustang Forum

LinkBack Thread Tools
post #1 of 7 (permalink) Old 05-10-2008 Thread Starter
8892mustangs's Avatar
Joined: Feb 2008
Location: lake city
Posts: 19
while driving rpm's drop engine stumbles then dies, 1992 Mustang 5.0

1992 5.0L, trick flow cyl heads, 1.6 roller rockers, 70mm t.b and egr.
under drive pulleys, upper and lower street heat trick flow and automatic tranny,bassani shorty headers,

now for my problem is the car starts off fine, once it warms up and driving the rpms drop to about 500 ,backfires, it feels like the transmission is about to fall off the car then it dies.

have to wait like 15-20 minutes before it will run, then it repeats it all over again, with the waiting, then it starts.

do i have a bad tps or byb valve, could i get a little help, im highly stress, every one i know is just carb and just are no help to me but telling that i can not fix it.

8892mustangs is offline  
Sponsored Links
post #2 of 7 (permalink) Old 05-11-2008
5.0L Member
cetchup's Avatar
Joined: Apr 2008
Location: charlottesville
Posts: 5
hey I have the same heads as you and when I first got it started I had some of the same problems. when you adjusted you rocker arms make sure you tighten down the poly locks on your rocker arm bolts good, also if you just put on the TB make sure you adjust the idle on it.

cetchup is offline  
post #3 of 7 (permalink) Old 05-11-2008 Thread Starter
8892mustangs's Avatar
Joined: Feb 2008
Location: lake city
Posts: 19
hey james how u doin?

thanks for the feedback, i will check everything you mention. what rpm r u idling in drive, park ect. also i tried to adjust my tps and could not get it to set any lower then 1.026, my understanding is that .997-.999 is the highest for n/a engines and 1.0 for the pwr adders. do u have any info on this.
well i fail to mention something in the first ?. my car was running well but when i arrived at the mech shop he told my timing was off b/c my #1 rotor must be at 12o'clock position, because the haynes manual has it that way, b/c that is for stock dist. i have a mallory and my #1 changed to the 9oclock position, car was great until he swap it to 12.

also have you ever had a beeping noise from behind the glove compartment. thanks again

Last edited by EagleAutosports; 05-11-2008 at 10:59 PM. Reason: merged 2 posts
8892mustangs is offline  
post #4 of 7 (permalink) Old 05-11-2008
4.6L Member
5.0L Member
EagleAutosports's Avatar
Joined: Feb 2007
Location: Graham
Posts: 46,030
Your rotor button should point at the #1 post on the distributor cap, and it won't necessarily by at 12 o clock or not, it'll depend on your timing setting, whether it's advanced or not. If it ran better before he fiddled with it, put it back the way it was.

And the beeping sounds like the airbag control module, it's behind the radio.

Best Car & Motorcycle Insurance | Auto/Moto Protection Today | FREE Trade-In Quote

AFM Site Administrator
Member: Mustang Club of America #82740, White Mustang Registry #362, NMRA, Fun Ford Weekend, Mustangs of Burlington

MOOG Certified Technician
For mods and sound clips, see profile and gallery.

EagleAutosports is offline  
post #5 of 7 (permalink) Old 05-26-2008 Thread Starter
8892mustangs's Avatar
Joined: Feb 2008
Location: lake city
Posts: 19
well i finally figured out what the beeping noise from under the dash was, the srs module was making it, and according to the manual mandotory to bring in to dealer for troubleshooting.

now i have the problem of the car starts off fine i drive it a while , then i shut it off and it will not start and if does it only idles at about 500 rpm and has no throtle respond.

so far i have checked the timing,tfi module, replaced fuel filter,ignition coil. but not any changes.

8892mustangs is offline  
post #6 of 7 (permalink) Old 05-28-2008
jimmihawk's Avatar
Joined: Jun 2006
Location: Key Largo
Posts: 6
Try it

Try a new map sensor mine did same thing.I took one off of my friends Ford van and problem solved, I went and bought a new one.Backfiring can destroy the sensor.
jimmihawk is offline  
post #7 of 7 (permalink) Old 05-28-2008
Sic89GT's Avatar
Joined: May 2008
Location: El Paso, Tx
Posts: 30
on my 89 5.0 I had the same problem of driving and the rpms drop and all the same stuff youve been having. If its still doing it, Replace the Ignition Moduel on the side of the Distrubtor becuase that was what was making mine die while driving and backfire and not want to start for awhile. just make sure to put the de-eletric grease on the backside of the new one cuz it is a VERY sensitive part.

Sig area isnt like the rest of the Forum sites... no images, no urls.
Sic89GT is offline  
Sponsored Links
Closed Thread

Quick Reply

Register Now

In order to be able to post messages on the Ford Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a VALID email address for yourself, otherwise you will not receive the necessary confirmation email needed to confirm, validate and activate your new AFM member account.

Failure to provide a VALID email address, will result in the cancellation of your new AFM member account registration.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

For the best viewing experience please update your browser to Google Chrome