Car wobbles when accelerating

Discussion in '2015+ S550 Mustang 5.0L Tech' started by Nikotopless, Apr 19, 2022.

  1. jewc75

    jewc75 S197 Junkie S197 Team Member

    A tune will void the warranty you have, id put it back to stock, all you need is the stock airbox. I might have one in my junk pile.
    Nikotopless likes this.
  2. DieHarder

    DieHarder Senior Member

    Like doctor's diagnosis' when you're not sure you're getting the full story; get a second opinion.... Since you have an extended warranty you can take it to a different dealer. Your warranty should be good everywhere; not "just" that dealer. Who knows, you might get lucky and get a mech/tech/someone with better experience or even possibly has seen this kind of problem before. You're not locked into just one servicing dealer.
    Nikotopless likes this.
  3. Pentalab

    Pentalab forum member

    The Ford warranty is good anywhere in North America.
    crjackson and Nikotopless like this.
  4. Nikotopless

    Nikotopless Junior Member

    The warranty I have is the “Ally Extended Warranty”
  5. 86GT351

    86GT351 forum member

    Thats generally sold by GM dealers
    crjackson, Nikotopless and jewc75 like this.
  6. Nikotopless

    Nikotopless Junior Member

    Yeah… bought the car at a Chevy dealership
  7. redfirepearlgt

    redfirepearlgt forum member

    That is NOT a No Tune Required JLT CAI. The dealer that told you the car is stock lied or has no clue about the simplest things. The peddle commander as well is NOT a factory device which again makes the car no longer stock. Chances are that the tune on the car caused the cylinder 8 failure to begin with. Over aggressive canned tunes (for no softer term) are notorious for causing this to happen prematurely.

    You should count yourself fortunate that the dealer covered the engine replacement under warranty. Again assuming they are NOT a Ford dealer. Had you taken the car to a Ford dealer (and if you did I want their named PM'd to me so I can use them in the future) they would have popped the hood, seen the after market CAI, scanned the PCM (ECM) and seen that the tune had been modified and told you, "sorry Charlie" with regard to any remaining Ford factory warranty on the car. JLT does make what they call a No Tune Required CAI but it looks nothing like the one on your car and is enclosed and has a smaller MAF housing tube so that proper air metering will take place with the factory tune. With the CAI you have on the car (if the factory tune has been reflashed) the engine will run very lean because more air is getting past the MAF than it is calibrated for due to a larger diameter MAF tube. LTFT's will be through the roof trying to correct for the lean condition if the factory tune is in place and would likely eventually generate a CEL and on a 15+ possibly a wrench (limp mode) condition as well.

    As mentioned, get a factory closed airbox, remove the stupid peddle commander gimmick, take the car to a Ford dealer and have them reflash the factory tune into the car and verify that all body modules are properly communicating to each other and the PCM (ECM) on the CANBUS network. Then put the factory airbox back on the car and drive it. If you are still having issues you at least now have a baseline to work from that a reliable Ford dealer can assist you with...though there will be no warranty aside from an extended warranty you have purchased. That extended warranty may be honored by a Ford dealer. Ask. The worst they can say is no. Or contact the warranty company and ask what if any Ford dealers in your area are honored by them. Taking a Ford to a Chevy dealer for problems like this is like taking a Samsung TV to a Zenith dealer for repair.

    Best of luck to you. Sorry to hear about your issues.
    nyuk98GT, crjackson and Nikotopless like this.
  8. Nikotopless

    Nikotopless Junior Member

    Wow thank you for such an insightful response! Couple questions here if you don’t mind helping me out a bit.

    1. Is my warranty void for buying the car used at a Chevy dealership that ALREADY came with a JLT CAI + Tune? If so, how can they legally sell me an extended warranty that’s automatically voided since the car has been modded? (FYI I have Major Guard Warranty with Ally)

    2. Is it more likely that the tune caused the previous misfire or the JLT CAI alone?

    3. How likely/possible is a dirty and improperly maintained air filter on the JLT CAI to cause a misfire? (Just checked and it looks pretty dirty so I’ll be cleaning/replacing the filter)

    4. What can cause a tune to be “corrupt?”
  9. redfirepearlgt

    redfirepearlgt forum member

    1.) Ask the warranty company you purchased through. I am speaking of any Ford original warranty. I have heard that there are a few warranty companies that will cover modified cars. I am not a warranty purchaser myself.

    2.) Depends mostly on who tuned it. If it was tuned by a reputable tuner like Lund, VMP, or Palm Beach less likely. Regardless if it was under a Ford warranty which it is past that now, it would have been voided in most cases. There are a few exceptions such as Roush or Edelbrock Supercharger packages that carry a blanket warranty option, but here again it only covers anything that Ford would otherwise not and is additional cost. There are less reputable tuners out there that offer basic canned tunes at a much lower price and promise the world. Additionally if being tuned on 93 and the car had 87 pumped into it that could cause issues. If the car was tuned for E85 and had 93 or 87 put in it this could also lead to problems. Not knowing is your issue. Never buy a modified car without the tuner. I passed up several nice cars looking for my current project because they were modified beyond what I wanted, undocumented on the mods performed, or missing the flash tuner device.

    3.) unlikely none. A rich condition would likely be observed which would be seen in trending LTFT data more than likely. A rich idle would also be likely observed.

    4.) Hard to speculate. It may simply be that they have reflashed the PCM to the factory tune and with the mods it only now appears to be corrupted. But it is possible if the voltage on the battery was low when they reflashed the factory tune loaded but failed to load properly. The 2015+ cars are very picky about voltage when being flashed. In fact the guys at the speed shop I deal with will not reflash or load a tune update on a 2015+ unless they have a charger hooked up to it to ensure voltage stays up and does not sag over the very long download process compared to earlier models.

    Sorry cant be of more help.
    Last edited: May 22, 2022
  10. Nikotopless

    Nikotopless Junior Member

    You’ve been of tremendous help dude and I sincerely extend my gratitude for taking time to help me out! Just a few more questions if you don’t mind. You’re my only savior right now lol

    1. I definitely considered the possibility of gas octane levels affecting the car. Since I’m at a guess right now till I get the factory air box and reflash the tune which of the 4 octane levels (that I have seen in my state - New Jersey) is MOST likely for the car to be tuned for? 87, 89, 91, or 93? In other words, if you had to take a guess since there’s no other way of knowing, what gas is most PROBABLE to cause the least issues?

    2. I have never seen E85. What is that? An octane level? And why would anyone want such a low octane?

    3. What is LTFT data?

    4. In regards to your answer in #4, there has been NOTICEABLE voltage and electrical problems with my car. I’ve replaced the battery twice since having it for 9 months. Is this indicative of anything?

    5. In regards to the dirty intake filter, if it wasn’t properly maintained and cleaned couldn’t that “sandblast” the engine and possible cause a misfire? I’m terrified that if I don’t resolve this ASAP I’m on the road to another misfire!

    6. Instead of reflashing the tune and installing the factory air box, can I just get it “retuned” or properly tuned somewhere?

    7. Assuming I have an overly aggressive CAI tune running or some corrupted tune (which I think I have one or the other) does my driving pattern affect the probability of causing any issues? In other words, if I drive slow and smoothly instead of aggressive and fast will this help prevent any mechanical problems/issues? Or is it just a matter of time until a problem is created?
    Last edited: May 23, 2022
  11. crjackson

    crjackson Member

    Fuel - 15% Gasoline / 85% Ethanol mix
    (AkA: Corn or KoЯn as my wife calls it after her favorite band)
    Last edited: May 23, 2022
    Nikotopless likes this.
  12. redfirepearlgt

    redfirepearlgt forum member

    Sorry I missed this. I am not set up to receive alerts.

    1.) 93 or the next best. Never heard of anyone having issues with one tune over another with regard to OCTANE. Higher octane equates to more power possible due to the slower burn rate which allows for more timing advance.

    2.) someone else answered that. Don't have it? Don't worry about it.

    3.) Long Term Fuel Trims. They can tell a lot about how a car is running. This is a correction made once Short Term Fuel Trims exceed a max amount and stay there. The LTFT changes over time based on how STFT is reacting in the tune. It is all about AFR vs LambSE on each bank. AFR is provided from the O2 sensor and LambSE is the calculated AFR target at a given throttle position to keep it simple. The difference between the two is reflected in STFT. IF STFT stays at a value long enough LTFT will change so that STFT can return to 1.0 (or 0.0 in some datalog processes). This number may be positive or negative.

    4.) You need to look at this closer. IF the voltage rectifier on the Alternator is going bad the unit will allow AC voltage to pass. This reaks problems on the entire system. There are tons if threads on it.

    5.) Not likely. Never heard of such a thing. I have only seen one time where an air filter on a friends car was so dirty that when he replaced it the car actually started running massively better. The filter had over 50K on it and it was in Southern California where there is tons of dust. The filter is exactly that a filter to trap dirt.

    6.) Yes

    7.) Any time you drive a car easier it reduces the risk of failure mechanically. It would require a Crystal Ball to answer that any more precisely and mine is out for recalibration and they have no idea when it will be ready. LOL!
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