engine stumbling

[pinbot1966]

??? 8)Took Boss back to dealer today.....they called ME to bring for a second attempt at correction! As of 4:00 PM, they have tried twice to repeat issue, one with tech & once with svc. mgr., with no stumble. Ford Tech line was called and they are waiting for reply.....keeping car indoors overnight!
When I get Boss back, will try disabling advance-trac. Have not noticed when using track key, but have used very little, and issue is intermittent. Will keep you all posted!
8)

Curious to know how many miles were driven (1-5, 5-10 miles etc.) when they tried to duplicate your concern with the flight recorder. In my case it took a 45 mile drive with the flight recorder to figure out what was occurring (previous attempts with 1-5 mile diagnostic drives yielded nothing).

From the tech's/service department's perspective, they want to invest the least amount of time to diagnose a concern if there is a possibility that they will not be be able to duplicate the customer's concern and not be compensated (by either FoMoCo warranty department or the dealership) for their diagnosis time.

I hope you are able to get your issue resolved.

 

[bullitt]

To pick up tomorrow -- tech and svc. mgr. has driven and warmed up well, they say. I will find out how many miles driven when I pick up. May be able to get some info from Ford Racing tech line, if any other complaints. Sure miss the Boss!

 

[bullitt]

Tech took out 3 times for a total of 21 miles -- evidently not enough to spring any faults on flight recorder. Work order open due to my wanting car back last Friday for this week's cruise. To return after this week for further check out @ dealer (located across street from FRAP!).

 

[bullitt]

Nothing to report as yet, due to floods in area and MOCSEM events, did not make Woodward Cruise. Work order still open at dealer. Will report any news when available.https://trackmustangsonline.com/Smileys/default/huh.gif

 

[bullitt]

Saw ad in latest Mustang Monthly mag for a PedalMAX , by JMS Chip & Performance. It plugs in between acc. pedal position sensor and vehicle harness to eliminate stalling and improve throttle response -- anyone tried or have thoughts? May cure some of the stumbling & stalling some of us have experienced? Appreciate feedback.

 

[WinterSucks]

As far as I know, the pedal is just a dumb encoder so I seriously doubt it has anything to do with stalling unless it is broken and confusing the ECU. Throttle response is determined by the ECU after it reads the position of the pedal and does some math and filtering. If this chip actually increases throttle response then all it is probably doing is multiplying the encoder counts to trick the ECU into thinking you are pushing the pedal more than you really are, so It might feel snappier but you are still going to get 100% in the end. I am wary of any "chip" for any modern car. There is nothing missing from these cars to modify throttle response, everything is implemented in firmware. Track key programming will increase throttle response and an AED tune will also. A lot of these "chips" are snake oil. Just a resistor to screw with MAF readings and potentially damage the engine.

 

[bullitt]

Thanks for the feedback -- confirms my suspicions. I do not have issues when using track key, only street key, so it appears to be basic factory tuning problem. Have heard good things about AED tune & may resort to that after warranty is expired.

 

[A10ACN]

Was there any solution to this? Mine has been this way since day one. Stumbling and coughing below 3000 rpm, about the range to drive in pedestrian areas. Noticed with Black and Red Keys. No mods for me other than Red Key and side discs out.
Anyone else with same issues?

 

[WinterSucks]

I have not had a stumble or surge if I let her warm up at least till the RPMs go down to idle at 850-900. Even if she is already warm, if I interrupt that warm-up routine of the ECO by touching the pedal or driving off right away then I get a surge suddenly while in gear. Something in the ECU is screwy. But if I take my time and sit 30 seconds to belt in, adjust radio, open windows, disengage traction control, etc, then that is all the time she needs.

Also, some guys have had transient issues with the TB and had it replaced under warranty.

Not saying this is a problem, but a few GT owners on AFM have complained about throttle response and rumbling. Then say they are shifting at 1400 RPMs into the next gear... They must have learned stick on a diesel.

 

[A10ACN]

For me its just low RPM driving around city streets and neighborhoods, below 3000 RPM. Its with both keys. I'm in Europe now, so don't have ready access to a dealer.

 

[WinterSucks]

There are service manuals up on the internet so you might be able to find some troubleshooting steps there. It could be as simple as a leaky vacuum hose.

If you have no dealer to help out and are not worried about the warranty then I am curious if a tuner like AED could help since they have you install a tune and then data log and send them the data. And hopefully that data log would show some of the odd behavior. If you contact them and buy a tune they might be able/willing to help.