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Dead-spot in gas pedal on my '05.....

9K views 46 replies 20 participants last post by  Strongjeff 
#1 ·
I seem to have this annoying dead-spot in my 2005 grand cherokee when i get to around 40 mph. I have the 5.7 liter hemi. Has anyone else experienced this? The only way to get the car moving is to put the pedal to the floor. Is this the overdrive or is it something else that needs looking into? The only mod i've done so far is flowmaster 50 series exhaust. Should i get a tuner and see if it solves the problem? Could also be time for new plugs & wires. Any advice is greatly appreciated.
 
#2 ·
It's most likely MDS kicking in. MDS kicks in between 40-60 mph and can be disabled with a diablo predator.
 
#3 ·
Dead spot in the gas pedal...well...first time I've ever heard of that.

Perhaps you need to reset the PCM? Since your throttle body/gas pedal is controlled by the computer and not a cable. May be there is just a glitch somewhere. Undo the battery for like 15 mintues and put it pack together and see if that fixes it..
 
#4 ·
sounds like the typical 5.7 slow throttle repsonse. I have heard from 5.7 owners that there is a delay. It could also be the mds if yoiu are cruising on the highway
 
#5 ·
i think i know what your talking about, if your aiming at the sluggish accel around that speed its normal. just the tranny being to low in RPMs to provide the ass, but the jeep wont downshift unless you peg it. its a fuel econ thing with the tranny control i believe. i used auto stick to speed past it.
 
#6 ·
Mine used to do this too. Very annoying. Here's my take on it. At that speed (around 40 mph) at light throttle is when the transmission is going nuts, IMO. It's right at/after the 3-4 shift point, MDS may or may not be trying to cycle, and the converter clutch may or may not be trying to kick in. Any slight throttle movement causes it to attempt to reverse some or all of these actions. If you have the MDS "ON" light you can see when the MDS cycles, and feel when some of the other actions occur. I have the Superchips tuner which has pretty much eliminated the problem by modifying the shift schedule and MDS parameters. I run the 91 tune. I also have a Dash Hawk on order. With that I'll be able to further monitor engine and trans. activities. I've got it on my Hemi Magnum and it's a must, IMO.
 
#7 · (Edited)
He has an 05 and there's no MDS light that shows when MDS is engaging. The problem isn't the transmission going nuts. It is MDS engaging.
 
#10 ·
Is the TSB on the 5.7's as well? I haven't seen it.
 
#11 ·
#12 ·
That TSB is for the 4.7 not the 5.7.

18-004-0902/06/09FLASH: HESITATION FEEL BETWEEN 38 TO 45 MPH (4.7L)
(superseded by 18-004-09b dated 10/30/09) X 18-004-09a04/01/09FLASH: HESITATION FEEL BETWEEN 38 TO 45 MPH (4.7L)
(superseded by 18-004-09b dated
 
#13 · (Edited)
Hemibeast, I would recommend that he ADD an MDS "ON" light if he hasn't already. I did it to mine 3 days after I got mine. It's easy to do. See the "how to" write-up that I did about 4 years ago over at LXForums.com, Knowledge Base. My screen name there is "magnuman". Wiring and pinouts are the same. Routing of wiring and light mount location are the only things that may differ. It's actually easier on the WK than it was on the LX.

Also, where did you mount your Billet Tech. Catch Can? I did one too, but it wouldn't mount in the same place as it does on the LX. I mounted mine to the support that goes over the engine.
 
#14 ·
Gotcha bro...
 
#15 ·
What do yo have now a 4.7 or 5.7?
 
#17 ·
Nice.... you won't need autostick once you receive the predator and disable MDS. And when your ready for a CMR tune pm Tom@ modern horsepower performance.
 
#19 ·
yes...the tsb is covered under the 7/70. I had this tsb performed. It is for tranny lug. I never experienced the tranny lug...but its updates the tcm. Beware...if you have a superchips...you will have to update your tune with superchips
 
#21 ·
Even with MDS disabled, steady cruising at about 40 MPH will drop the tranny into 4th gear, and you'll probably be turning somewhere around 1300-1500 RPM. If you give it throttle and it doesn't downshift, you're way too low in the powerband to get any kind of real acceleration - hence why you gotta kind of goose it to get it to downshift.
 
#22 ·
I have a 3.7 and I eperience lag all the time, mostly going up hills. It feels like its in a higher gear than it should be with lower rpm's. Im used to putting the throttle to the floor to make it downshift, but its annoying and doesnt feel right. I never experienced this in my previous 5.2 GC's.
 
#23 ·
Here's a question that may be dumb, but I have never taken my car to the dealer to have anything "flashed", would I benifit from it or does something have to be "wrong" with the car, like can they just hook it to a machine and reprogram everything to newer specs or however they do it?
 
#26 ·
nope....only if you are under warranty. And...it will just be the flash that is prescribed...so to speak. Like...you cant just go in and theyll flash the entire pcm/tcm....
 
#28 ·
What about re-calibrating the throttle? It's the Drive-by-wire stuff in the 'adaptives' no?

Here's the steps you need to follow:
1. Find an unused section of road with a good spot to pull-off/turn-around.
2. Pull off of the road and shut your car off.
3. Turn your key to the "On" position (but don't start the car), and wait for the 'idiot' lights to go out.
4. Press down on the accelerator, and let it back up.
5. Turn your car off.
6. Re-start your car and cruise up and down the road testing your throttle responsiveness.
Depending on how fast/slow you do the 4th step, your throttle will either become more or less sensitive/responsive.
Repeat steps #1 through #5 as needed until you're satisfied that your throttle response is as good as it's going to get.

Remember these things 'learn' how you drive so if you drive like Grandma for a few days, it's adjusts accordingly.
 
#31 ·
What about re-calibrating the throttle? It's the Drive-by-wire stuff in the 'adaptives' no?

Here's the steps you need to follow:
1. Find an unused section of road with a good spot to pull-off/turn-around.
2. Pull off of the road and shut your car off.
3. Turn your key to the "On" position (but don't start the car), and wait for the 'idiot' lights to go out.
4. Press down on the accelerator, and let it back up.
5. Turn your car off.
6. Re-start your car and cruise up and down the road testing your throttle responsiveness.
Depending on how fast/slow you do the 4th step, your throttle will either become more or less sensitive/responsive.
Repeat steps #1 through #5 as needed until you're satisfied that your throttle response is as good as it's going to get.

Remember these things 'learn' how you drive so if you drive like Grandma for a few days, it's adjusts accordingly.

So taking what you wrote, in that driving like grandma for a few days it will adjust to that driving, so then driving like a race car driver for a few days should make it adjust accordingly and make throttle response pick up more? No?
 
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