Search



Go Back   MustangForums.com > Ford Mustang Tech > V6 (1994-2004) Mustangs
Sign in using an external account
Register Forgot Password?
Search

V6 (1994-2004) Mustangs Technical discussions on the 3.8L and 3.9L V6 torque monsters
Sponsored by Optima Batteries


Welcome to Mustang Forums!
Welcome to Mustang Forums.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!


Reply
 
 
 
 
Thread Tools Search this Thread
Old 04-01-2009, 08:24 PM   #1
RonnieD
1st Gear Member
 
Join Date: Feb 2006
Posts: 85
Default rough idle

--------------------------------------------------------------------------------

Okay symptoms:
rough idle
strong gas smell at idle
bad gas milage barley seeing 20 with only freeway miles, im getting roughly 13 on city driving.
long crank til start.
And when i get off the gas, and coast, my idle floats around 1000-1200.

Now I thought it was my IAC, but i do not have any issues with a drastic change in idle when i put more acc. loads on the engine. An IAC wouldnt give me bad highway milage would it? Im not at idle.

I suspect a leaky injector, (not fully seating) hence why its so much worse in city driving mpg cause im more stop and go.

I dont have any tools really at my house, I might go pick up a fuel pressure gauge at autozone and see if i get pressure drops at the service port on the rail.

What else could cause my issue?

I also suspect it being an injector because it doesnt have a rough feeling like a miss in every fire, it as if one cylinder is missing at idle, though im not throwing any codes, and the 4 gas anylzer showed no signs of rich condition when i smogged it, though the numbers were read under a load.. so i dont hold much validity to them.
This ad is not displayed to registered or logged-in members.
Register your free account today and become a member on Mustang Forums!
RonnieD is offline   Reply With Quote
Old 04-01-2009, 08:38 PM   #2
bigjj92
1st Gear Member
 
bigjj92's Avatar
 
Join Date: Dec 2008
Vehicle: 2003, ford, mustang
Location: fl
Posts: 93
Default

you can put some fuel injector cleaning liquid, that always help you get higher mpg.
__________________
MODS
-CAI from AM
-Dual Flowmasters


SOON TO COME
-SCT Tuner


Quote:
Originally Posted by Project6 View Post
f u c k you all dik riding faggets! my v6 cobra owns you all!!!!!
bigjj92 is offline   Reply With Quote
Old 04-01-2009, 09:50 PM   #3
RonnieD
1st Gear Member
 
Join Date: Feb 2006
Posts: 85
Default

I have run injector cleaner through with a full tank once before, I have even run seafoam through the gas, crankcase, vacuum line. Still nothing.

The car was nearly wrecked before, and sat for about 8 months in my driveway. Then sat at the body shop for another year and a half.

Could this have anything to do with the gas sitting for so long, possibly picking stuff up and damaging the injector when it started to be ran again?

Im not just trying to get better milage either, i want to fix my idle

Last edited by RonnieD; 04-01-2009 at 09:58 PM.
RonnieD is offline   Reply With Quote
Old 04-02-2009, 02:12 PM   #4
haystackstang
2nd Gear Member
 
haystackstang's Avatar
 
Join Date: Nov 2006
Vehicle: 1996 Mustang
Location: Ca
Posts: 490
Default

Quote:
Originally Posted by RonnieD View Post
I have run injector cleaner through with a full tank once before, I have even run seafoam through the gas, crankcase, vacuum line. Still nothing.

The car was nearly wrecked before, and sat for about 8 months in my driveway. Then sat at the body shop for another year and a half.

Could this have anything to do with the gas sitting for so long, possibly picking stuff up and damaging the injector when it started to be ran again?

Im not just trying to get better milage either, i want to fix my idle
yeah im pretty sure thats not a good thing
__________________
haystackstang is offline   Reply With Quote
Old 04-02-2009, 04:20 PM   #5
99V6Auto
1st Gear Member
 
Join Date: Jan 2009
Vehicle: 99 Mustang V6 auto
Location: Oklahoma City
Posts: 55
Default

DO a fuel pressure check/see if it bleeds off after shutdown, if that checks good then do a compression check, if thats good do a cylinder leakdown test, if thats good check for bent pushrods, if those are good do a tune up (that should be 1st anyway). Post back after those are done
99V6Auto is offline   Reply With Quote
Old 04-02-2009, 07:42 PM   #6
jthorn9
The Godfather

 
jthorn9's Avatar
 
Join Date: Sep 2005
Vehicle: 2008 Mustang GT
Location: College Station, Texas
Posts: 15,365
Jeremy Thorner jthorn9
Default

Your problems are coming from one of several areas:

I can tell you that there is almost zero chance it's a fuel injector not seated because of the way the fuel rails mount, there are 4 small bolts that hold the rails in place, so unless the thing is bent there is no way for the fuel rails to release enough pressure on the injectors for one to become unseated.

*IAC (yes a bad/faulty IAC will cause a horrible idel)
*Clogged/Faluting EGR Valve or Sensor (if this goes out it can serriously through off the a/f mixture
*Faulty Temp Sensor (if this goes out the engine will run rich as the sensor isn't telling the ecu that the engine is now warm and doesn't need to dump extra fuel into the cylinders)
*Faulty/Dirty MAF Sensor (if the MAF is faulty or dirty this would cause the sensor to send bad or no information to the ECU and the ECU wouldn't know how much fuel to add for the air comming in)
* Unlikely, but Throttle Position Senor could be faulty (this would cause a bad idel, but wouldn't explain the car running rich)
__________________
Serenity 08 Mustang GT - 295 RWHP, 315 TQ
Shelly 11 Mustang V6 - 270 RWHP, 260 TQ

95 Mustang 5.0 - N/A 250 RWHP, 275 TQ; S/C 400 RWHP, 400 TQ (sold)
99 Mustang SVT Cobra - 280 RWHP, 290 TQ (sold)
97 Mustang GT - 190 RWHP, 250 TQ (sold)
00 Mustang V6 - 145 RWHP, 184 TQ (sold)
98 Mustang V6 - 125 RWHP, 210 TQ (sold)
jthorn9 is offline   Reply With Quote
Old 04-02-2009, 07:45 PM   #7
jthorn9
The Godfather

 
jthorn9's Avatar
 
Join Date: Sep 2005
Vehicle: 2008 Mustang GT
Location: College Station, Texas
Posts: 15,365
Jeremy Thorner jthorn9
Default

Oh, also, as you figured, a clogged Fuel Pressure Regulator could be to blame as well. Don't bother with Autozone for a meter, I went to mine and the guy looked at me dazed, he didn't know what the hell I wanted, but once I got it through his thick skull, he said they didn't sell them, you might have to go to either advanced auto parts, or another autoparts store, autozone has most things, but I didn't see this one at mine.
__________________
Serenity 08 Mustang GT - 295 RWHP, 315 TQ
Shelly 11 Mustang V6 - 270 RWHP, 260 TQ

95 Mustang 5.0 - N/A 250 RWHP, 275 TQ; S/C 400 RWHP, 400 TQ (sold)
99 Mustang SVT Cobra - 280 RWHP, 290 TQ (sold)
97 Mustang GT - 190 RWHP, 250 TQ (sold)
00 Mustang V6 - 145 RWHP, 184 TQ (sold)
98 Mustang V6 - 125 RWHP, 210 TQ (sold)
jthorn9 is offline   Reply With Quote
Old 04-03-2009, 02:24 PM   #8
RonnieD
1st Gear Member
 
Join Date: Feb 2006
Posts: 85
Default

The tps and maf are not the problem.

If the problem was an egr related one, i would have seen this on the gas anlyzer. Not an egr.

I doubt the iac still, because it is not a horrible idle, its more of a constant one, but you do notice their is a problem with it. It still wouldnt explain my gas milage. They have no play in metering air around that throttle plate once that throttle plate is opened.

Jthorn, I was not talking about the seat to the rail, sorry terminology is gettin across wrong, I was taught that seating with diagnosing an actualy injector meant the needle of the actuator. Meaning its dripping fuel when its not spraying.

A gauge could tell me this If I use it at the service port, but will not tell me which one. You would have to clamp the return, so that you hold pressure from the clamp to the injectors, and if your pressure drops, its not going backwards, cause you clamp it. Meaning its leaking at the actual injectors.

I have not gotten a gauge, about 30-40 bucks at autozone with the ford service valve fitting. They do sell them, somtimes you just have to look for yourself. Or go to a main store. Usually the 24 hour ones around here. I just havnt had the money to pick one up right now. Spending money on gas for school, and I dont have the diagnostic classes anymore so i dont have access to the tools. Im taking a climate control class.

So im stuck with a leaky injector, and another forum gave me the suggestion of the 02 sensors, which are not dead, cause I havnt gotten a code. Maybe going bad, with a very slow response rate, which could explain my mpg, but not my idle.
RonnieD is offline   Reply With Quote
Old 01-28-2011, 08:31 PM   #9
FAST 5.0
 
Join Date: Jan 2011
Vehicle: 1989 ford mustnag 5.0
Location: California
Posts: 2
Default

im have kinda the same issue bad idle, car has a e 303 cam bbk cold air intake edlbrock performer 2 upper and lower intake. SOme time when i come to a light the idle dropps a low or it trys to die out on me if i dont give it a liitle gas. When it does idels it jumps around so check engine light came on yesterday and when it does it idels high above 1k rmp and hen trys to shut off. could this be some of my issues that the guy stated in yours.
FAST 5.0 is offline   Reply With Quote
Old 01-28-2011, 08:31 PM
MustangForums
Ford Mustang




Paid Advertisement

 
 
 
Reply

Tags
2004, 38, 39l, 94, 99, backfire, backfires, egg, gas, idle, mustang, rough, smell, times, v6

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Rough Idle at startup? 07redMustang V6 S197 General Discussion 12 08-09-2008 08:31 AM
rotten egg smell and rough idle - ideas? SOHCtimes2 4.6L (1996-2004 Modular) Mustang 21 01-24-2008 02:13 PM
Rough idle on 66 coupe BreakOut Classic Mustangs (Tech) 26 01-02-2008 03:06 PM
stumped on rough idle bugmenot V6 (1994-2004) Mustangs 10 04-01-2006 01:41 PM

Advertising

Featured Sponsors
Vendor Directory
New Sponsors
All times are GMT -5. The time now is 10:28 PM.

© Internet Brands, Inc.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.5.2

This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company
Emails Backup