[BOBFOX]

I just recently got my car out of the barn for the first time this spring. I have always noticed that after accelerating especially hard acceleration if you push in the clutch to coast or slow down the engine rpm's surge from between 500 to 1,200 rpms.

Sense I have gotten the car out this spring it has stalled on me 3 times while decelerating with the clutch pushed in (rpms are surging), and every time the car will start back up and run fine.

It has thrown a trouble code saying that bank one is lean, which has left me wondering what could be causing my problem and why has it started sense coming out of storage?

 

[rpretzel]

I just recently got my car out of the barn for the first time this spring. I have always noticed that after accelerating especially hard acceleration if you push in the clutch to coast or slow down the engine rpm's surge from between 500 to 1,200 rpms.

Sense I have gotten the car out this spring it has stalled on me 3 times while decelerating with the clutch pushed in (rpms are surging), and every time the car will start back up and run fine.

It has thrown a trouble code saying that bank one is lean, which has left me wondering what could be causing my problem and why has it started sense coming out of storage?

Take her to the dealer. A lean code is not good.

 

[Svtbird91]

I just recently got my car out of the barn for the first time this spring. I have always noticed that after accelerating especially hard acceleration if you push in the clutch to coast or slow down the engine rpm's surge from between 500 to 1,200 rpms.

Sense I have gotten the car out this spring it has stalled on me 3 times while decelerating with the clutch pushed in (rpms are surging), and every time the car will start back up and run fine.

It has thrown a trouble code saying that bank one is lean, which has left me wondering what could be causing my problem and why has it started sense coming out of storage?

Check all your intake hose connections to make sure they are not loose or (sucking air ).

If everything looks tight then take it to the dealer and have them check it out like rpretzel suggested.

 

[shlbysvt]

Having rough idle and car breaking up till engine has run for some time and reached operating temperature. Not throwing any codes, but do not like the hesitation till engine settles in. No vacum leaks or intake issues. Running an Evo. tune but only input from Fred is to dyno it. Any suggestions?

 

[Svtbird91]

Having rough idle and car breaking up till engine has run for some time and reached operating temperature. Not throwing any codes, but do not like the hesitation till engine settles in. No vacum leaks or intake issues. Running an Evo. tune but only input from Fred is to dyno it. Any suggestions?

If this is a new sympton then I would first try disconnecting the batt for a few minutes then try it. It will reset the tune.

 

[shlbysvt]

Already tried to no avail. Sent the tuner to Evo to erase the tunes and check the files. Maybe a corrupt file.

 

[cobramach1]

Sounds like your IAC valve is going bad. Most common reason for what you are describing.

 

[Svtbird91]

Already tried to no avail. Sent the tuner to Evo to erase the tunes and check the files. Maybe a corrupt file.

Do you have the monoblade TB on the car or the stock one ?

 

[shlbysvt]

Do you have the monoblade TB on the car or the stock one ?

Stock.

 

[shlbysvt]

Sounds like your IAC valve is going bad. Most common reason for what you are describing.

Not having much luck. Can you be more specific as to what the IAC valve is. I have Bassani Headers and Fred says they are noted for exhaust leaks and could be causing the problem. Nice to know after they sold me the product. Anyone else experiencing a similar problem with Bassani's. Once again the car breaks up on initial start and engine runs rough till car settles in after about five minutes. This will happen every time on the start up whether cold or warm. On deceleration almost has a slight back fire or gargle in the exhaust tune. Tried cleaning the MAF with little or no improvement.

 

[cobramach1]

Not having much luck. Can you be more specific as to what the IAC valve is.

Idle Air Control valve and it should be on the back side of the intake. I don't think they cost a great deal to replace and they are only a few bolts to replace. It may just need to be cleaned. I know where the one is on my 4.6 32v Mach1, but I've never looked where it's at (because I've never needed to) on a GT500. I imagine it's in the same area. It's right next to the throttle body on the back of the intake on the 4.6. I've personally never had a problem with one, but I know plenty of people who have. It seems to affect manual trans cars more too for some odd reason that I can't explain. I'm still very old school with a lot of my knowledge mostly working on engines such as the FE series of big blocks and the 385 series (429/460) as well as the 351C/M and 400 engines. If it's acting up, change it out with a new one. They do go bad. 9 times out of 10 the problem you're describing is either a dirty MAF screen or the IAC valve and since you've cleaned the screen, the IAC is your next likely culprit. Even if it doesn't take care of it, save the old one because it will go bad! I'm pretty sure that this is likely your problem though. I would bet money that the dealership would first try that as well.

 

[Svtbird91]

Not having much luck. Can you be more specific as to what the IAC valve is. I have Bassani Headers and Fred says they are noted for exhaust leaks and could be causing the problem. Nice to know after they sold me the product. Anyone else experiencing a similar problem with Bassani's. Once again the car breaks up on initial start and engine runs rough till car settles in after about five minutes. This will happen every time on the start up whether cold or warm. On deceleration almost has a slight back fire or gargle in the exhaust tune. Tried cleaning the MAF with little or no improvement.

The IAC is the idle air control mounted on or near the throttlebody and is controlled by the PCM.

 

[The Bone]

I just recently got my car out of the barn for the first time this spring. I have always noticed that after accelerating especially hard acceleration if you push in the clutch to coast or slow down the engine rpm's surge from between 500 to 1,200 rpms.

Sense I have gotten the car out this spring it has stalled on me 3 times while decelerating with the clutch pushed in (rpms are surging), and every time the car will start back up and run fine.

It has thrown a trouble code saying that bank one is lean, which has left me wondering what could be causing my problem and why has it started sense coming out of storage?

It seems to me that you get on it hard then push in the clutch to let it coast right.
If that is the case then what is happening is the throttle is wide open the you have lots of RPM.
Then you let off the gas and the throttle closes but the motor is still in high RPM.
The ECU is trying to figure what just happened can you see where I am going with this.the engine still has lots of RPM but the throttle is closed and the ECU wants to deliver more fuel for the RPM that the motor is having. But the motor is at idle with with the throttle closed so the ECU is only sending fuel for idle. The ECU may also be looking at the speed sensor and other things to determine how much fuel to deliver not just the ICU.
I never push in the clutch to let my car coast after hard acceleration as this is a bad thing for you're motor in my opinion.
Art

 

[shlbysvt]

Guys I have searched high and low for a IAC valve on the GT500 and I could not find one. Whether in the manual or on the TB. It must go by another name. What ever happend to the old tach and dwell? Man am I old school!

 

[joegaz]

Guys I have searched high and low for a IAC valve on the GT500 and I could not find one. Whether in the manual or on the TB. It must go by another name. What ever happened to the old tach and dwell? Man am I old school!

Based on what you posted earlier, I find it doubtful that idle control is your issue.If it not related to your tune, I would be more inclined to be looking for a sticking injector. Sticking injectors are a common problem for us on a fleet of DPS Crown Vics. We will usually add a bottle of Techron to the fuel and drive the car for 10 miles or so before we procede any further, 80% of the time the Techron does the trick.


If you did have an idle concearn, I did get this little info from Oasis:
20053 2007-2008 MODEL YEAR GAS ENGINE VEHICLES - HIGHER THAN NORMAL IDLE SPEEDS
SOME 2007-2008 MODEL YEAR VEHICLES EQUIPPED WITH A GAS ENGINE, WITH LESS THAN 50 TOTAL STARTS, OR LESS THAN 5 CONTINUOUS MILES OF DRIVING BETWEEN STARTS, MAY EXHIBIT HIGHER THAN NORMAL ENGINE IDLE SPEEDS. PLEASE INFORM THE CUSTOMER THIS IS A NORMAL CHARACTERISTIC. SERVICE SHOULD NOT ATTEMPT REPAIR. AFTER 5 CONSECUTIVE MILES OR 50 STARTS, THE IDLE SHOULD RETURN TO NORMAL.
EFFECTIVE DATE: 11/19/2007

I hope this might help
joe

 

[shlbysvt]

Based on what you posted earlier, I find it doubtful that idle control is your issue.If it not related to your tune, I would be more inclined to be looking for a sticking injector. Sticking injectors are a common problem for us on a fleet of DPS Crown Vics. We will usually add a bottle of Techron to the fuel and drive the car for 10 miles or so before we procede any further, 80% of the time the Techron does the trick.


If you did have an idle concearn, I did get this little info from Oasis:
20053 2007-2008 MODEL YEAR GAS ENGINE VEHICLES - HIGHER THAN NORMAL IDLE SPEEDS
SOME 2007-2008 MODEL YEAR VEHICLES EQUIPPED WITH A GAS ENGINE, WITH LESS THAN 50 TOTAL STARTS, OR LESS THAN 5 CONTINUOUS MILES OF DRIVING BETWEEN STARTS, MAY EXHIBIT HIGHER THAN NORMAL ENGINE IDLE SPEEDS. PLEASE INFORM THE CUSTOMER THIS IS A NORMAL CHARACTERISTIC. SERVICE SHOULD NOT ATTEMPT REPAIR. AFTER 5 CONSECUTIVE MILES OR 50 STARTS, THE IDLE SHOULD RETURN TO NORMAL.
EFFECTIVE DATE: 11/19/2007

I hope this might help
joe

Joe I have not tried the techron yet, but car idle searches on start up and seems to be running rich. I say this because the o2 sensors had alot of carbon build up on them as well as the exhaust tips. Think my next step is to get it to a diagnostic machine to see what is going on. Any input would be appreciated.

Thanks

Joe

 

[joegaz]

Once again the car breaks up on initial start and engine runs rough till car settles in after about five minutes.

I think the quote above is the part of your post I zeroed in on.
You mentioned 02 sensors, but I don't think 02 sensors are in the equation on your initial startup. After a few minutes of running as they get warm, they will come into play. I previously mentioned a possible sticking injector as I am thinking that you are burning off raw fuel when you first start the car.
Another failure that falls under your description, is a fuel pressure regulator leak. We have also seen fuel bleed off so bad that it washes cylinders and your engine oil gets fuel contaminated, causing rough running until the engine goes into "closed loop" and full engine control is maintained by the PCM.
But you are right about getting it scanned, as we could speculate this problem to death.
joe

 

[HorseTraderDave]

Not having much luck. Can you be more specific as to what the IAC valve is. I have Bassani Headers and Fred says they are noted for exhaust leaks and could be causing the problem. Nice to know after they sold me the product. Anyone else experiencing a similar problem with Bassani's. Once again the car breaks up on initial start and engine runs rough till car settles in after about five minutes. This will happen every time on the start up whether cold or warm. On deceleration almost has a slight back fire or gargle in the exhaust tune. Tried cleaning the MAF with little or no improvement.

Not my area of expertise, but I'd be surprised if it's a header leak given that you say it stops after the car warms up. One thing you can try us taking some type of starting fluid/chemical (gumout spray works well), use the little red tube that comes with it, and spray tiny amounts around each header connection. If one is leaking the idle will surge immediately.

I don't know enough about the engine management system to know what other components would cause your issue. I suppose you could try reflashing to stock to see if it goes away...thus eliminating the tune.

 

[NeedforSpeed]

Shlbysvt,

Did you every find the cause to "Erratic Idle While Decelerating
"?

Thanks

 

[shlbysvt]

Read the post above yours as mine was not an erratic idle while decelerating. My issues were tune combined with slight exhaust leaks pre-cat. Follow the thread and you may find the answers you are searching for.