"Textured Soy Protein" (texturedsoyprotein)
03/30/2015 at 22:48 • Filed to: None | 3 | 2 |
Tonight I did the !!!error: Indecipherable SUB-paragraph formatting!!! procedure on my Grand Cherokee. It cleared out the cylinder deactivation check engine code, and so far my bouncing idle and sluggish throttle response seem to be solved. Pretty good results for disconnecting/reconnecting the battery then twiddling the gas pedal in a specific pattern.
On the one hand, I could probably get away with just leaving it alone and returning the 4 oxygen sensors that I had ordered from Amazon, because the running-rich and cylinder deactivation codes, along with my poor gas mileage, may well have both been caused by the need for the throttle recalibration rather than bad O2 sensors.
But...just in case, I'm going to have the O2 sensors !!!error: Indecipherable SUB-paragraph formatting!!! , because a lot of the WK guys talk about replacing them around similar age/mileage to where I'm at. Can't hurt to have the fresh ones on there.
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JGrabowMSt
> Textured Soy Protein
03/30/2015 at 22:59 | 0 |
Youve done the EGR valve, right? Funky codes from the 5.7 are somewhat simple in that they're pretty easy to track down.
Considering the age, the cats may be starting to show signs of requiring replacement (along with throwing off O2 sensors if its really bad). Im having my whole exhaust done soon.
Also, th TPS reset is more for eliminating the dead spot or sluggish acceleration, but shouldnt be related to any rough idle or shaking. The MDS only activates between 18-55 mph as far as Ive read anywhere, and the only problem is when a solenoid goes bad. I would consider pulling spark plugs and checking how they look, along with just re-seating the spark plug wires.
Sometimes super simple things make the biggest difference.
Textured Soy Protein
> JGrabowMSt
03/30/2015 at 23:44 | 0 |
It got a fresh EGR, spark plugs, and air filter in December.
The cats are one of the reasons I'm sorta-proactively doing the O2 sensors. (Proactive in that I haven't yet gotten an O2 sensor code, just other codes that point towards O2 sensors as being a possible cause.) Because the O2 sensors going bad could foul up the cats.
At least among the Jeep Hemi guys, several of them have reported that a throttle relearn fixed their bouncing idles. Seems to have done the trick on mine. The idle bounce was really bad. It only started happening after the EGR was replaced, and had been getting progressively worse, to the point it was occasionally dying when I'd come to a stop. The first time I drove it after the relearn (which was to drop it off at the mechanic) the idle was pretty much rock solid. It'd dip like 25 rpm pulling up to a stop and then instantly recover. That may sort itself out with a little more time for the adaptive programming to learn my driving habits.
I also definitely had sluggish acceleration, and a dead spot when merging on to the highway—it'd shift into 5th way too soon and kill any acceleration until I gave it enough gas to kick back down to 4th or 3rd. That's gone now after the relearn. It actually feels sorta quick now.
The too-rich codes were thrown when I had pulled up at my mailbox one day and gotten a bad idle bounce. CEL came on, pulled P0172 & P0175 which are both mixture too-rich codes, one for each bank. They cleared out just fine.
The MDS code came on when I had been cruising on the highway for a good long while. The service manual mentions that MDS looks at several parameters including TPS and O2 in order to activate. The MDS code refused to clear with my cheapie OBD bluetooth dongle. When I did the throttle relearn, the CEL came on after I had pulled and reconnected the battery, but when I did the first slow press on the gas pedal for the relearn, the CEL blinked then turned itself off.
My theory is the potentially-dying O2 sensors combined with an out-of-whack throttle calibration caused the MDS code. But hey, it's just a guess. At least the CEL is off, and hopefully the relearn + fresh O2 sensors prevent any further issues. I got the proper NTK sensors, so I'm expecting to avoid any of the pitfalls caused by going with another brand.