XJ Cherokee Shudder

[-JC-]

Originally Posted by darksidecustoms

Being a Pre-update you should be able to read the codes without a diagnostic tool. See if you have anything stored, even if you don't currently have a check engine light.
http://www.go.jeep-xj.info/HowtoECUcodes.htm

Thanks for the link, followed the instructions and worked. . . great stuff! My error codes are:

12 - Battery Disconnected "Battery of power to ECM disconnected in last 50 key cycles." I'm guessing that this may have been done in the workshop when replacing the CPS, cat or ignition coil.

17 - Engine running too cold "Wrong of faulty thermostat"

44 - Battery temp sensor "Needs Specialist Diagnostics"

55 - End of Code

I know that 44 was one of the codes that the Jeep mechanic read before he reset the codes and the CPS & cat were replaced.

Not sure if any of these will account for the way that the Jeep currently runs?

It seems to be getting worse, the Jeep is now missing on idle. This morning is the first time I've had a miss on idle, before that it idled smooth as. This morning started, idled smoothly then a single miss, then smooth as and about 10 sec's later another miss and repeated 4 times.

Will look at the TB reset and cleaning TPS contacts next unless anyone's got any other ideas?

[-JC-]

Originally Posted by ApacheResistance

When you say "shudder" do you mean like a loss of power type of shudder, or like the jeep is actually shaking shudder?

Or is this "shudder" you describe kind of feel like the jeep is rolling backwards on the unibody yet the jeep is going forward? If it feels like a transmission slippage or something along those lines, i'd personally start looking at the TPS as the culprit.

Also, read this;

http://www.cherokeeforum.com/f2/free-quick-fix-41821/

That shows an adjustment you can make on the throttle body, and it appears that everybody is benefiting from it. However, skip to page (7) and read post #93. That's the one you want to follow!

Thanks for the link, I've now done the cable adjustment, it didn't move much (if any) from it's original position. Took the Jeep for a test drive and it seems to change higher in the RPM range than before on normal and low acceleration.

I also unplugged the TPS and cleaned the pins and re-plugged it in (saw a few posts where that made a difference.

However the Jeep is now running terrible, I doubt it is related to the TB cable adjustment but now it's regularly missfiring, especially under load. A normal misfire instead of the shudder it had before, can see the revs drop on the tacho as it misfires.

I'm gonna order a TPS and see how that goes

[mtd]

o2 sensors? car splutters/surges when one of those is stuffed. disconnect to see if problem goes away. if it does its them.

[ApacheResistance]

So you're saying you unplugged the TPS and plugged it back in, and right then and there the problem became worse?

If that's the case, i'd assume it has something to do with the TPS.

[-JC-]

Originally Posted by mtd

o2 sensors? car splutters/surges when one of those is stuffed. disconnect to see if problem goes away. if it does its them.

Thanks, for that. . . . I just disconnected both sensors but she's still running rough as.

I'll plug em back in once the exhaust cools down a bit

[-JC-]

Originally Posted by ApacheResistance

So you're saying you unplugged the TPS and plugged it back in, and right then and there the problem became worse?

If that's the case, i'd assume it has something to do with the TPS.

It looks like it. . . I'm ordering a new TPS from Rock Auto, they don't seem very expensive.

[ApacheResistance]

Originally Posted by -JC-

It looks like it. . . I'm ordering a new TPS from Rock Auto, they don't seem very expensive.

I don't order from Rockauto much, but make sure that has a lifetime warranty.

I buy all my electrical sensors directly from the dealer as a lot of sensors that are aftermarket are hit and miss with a lot of them being miss.

It's like $30 extra or so over here to just get a dealer part as opposed to aftermarket. (at-least for sensors.) Everything else i buy aftermarket.

You might want to buy a bottle of throttle body cleaner to clean the TPS and the IAC, and then a can of MAF cleaner to clean the MAF.

Just be careful as they're all super sensitive and easy to break.