Error codes, and other issues

[hinchcliffe]

The idle is revving up/down and now almost stalling. Driving along and is seemed to shut-off but the jeep was still on electrically. CEL went on and codes are for TPS/Manifold absolute and then multiple cylinder misfires.

Also, previously when coasting and it down shfts hard almost like you have just run over something in the road. Transmission fluid is being flushed and new filters going in today, not sure if that'll help or not.

What do you guys think?

[Matt]

Do you happen to know what the actual code numbers are? For instance P0300 will be your multiple cylinder misfire. Reason I ask is I'm wondering if one of the codes was actually indicative of a crank position sensor/circuit fault. That would lead to your running rough and stalling issues and could also result in P0300 since the ignition system in your vehicle relies on crank position for proper timing and firing order.

Im not sure if the computer would throw a TPS code for a crank sensor fault, but it's possible. It is however less likely for a faulty TPS to cause misfiring... hence my question.

Some other info that would help:
How many miles?
Have you done any recent maintenance or changed any parts?

[hinchcliffe]

Yes one code was P-0300, can't rememeber the other code number. But suppposedly the dealer we got it from cleared a code from the crank position sensor after they "washed" the engine and verified that the sensor was "OK". That's what makes me think its the crank sensor and then the TPS maybe getting a code becase of that and the cyl misfire. TPS wouldn't casue the cyl to have issue, but that could be why the pedal was acting wierd. Either way I'm going back on them to fix it correctly.

We bought this from a dealer to satisfy my wife's thinking that it'll be a good one, see where that gets you...... I'd still have rather got if from a private seller like I've always done, oh welll.

It's an '06 with the 4.7 and just turned 60k miles. I haven't done any maintenance yet since we just got it 1 week ago.

[Matt]

Oh I remember that thread now..... did you ever respond to my question of how they verified that the sensor was "good"? That sounded a bit sketchy to me.... especially since its really hard to get enough water on there to throw that fault unless the connector is bad.

Given that new info... I'd have them replace the crank sensor. Also you can hook up a scanner and watch the TPS readout as you press the gas. Make sure its a smooth transition as you press the throttle.

[hinchcliffe]

Never got nfo from them as to how "good" it was. A different dealer just did the error codes and diagnosed the TPS as bad, they want $315 to change it out on a $125 part. I'll get the part wholesale and change it myself and I'll see how it goes from there. They also check the plugs and said they were gapped incorrectly? So I'll do plugs tonight also.

TPS is bad to change on the 4.7, right? I did it on my 2001 4.7 GC, so I imagine a bit different with the drive-by-wire, but not bad. Which plugs should I get, copper ones right? I know on the 2001 the Platinum plugs weren't a good mix compared to the copper.

[Matt]

For the plugs definitely go copper.

Changing the TPS is easy. The only thing I'm not 100% sure on is if it requires any programming to initiate/setup. .. my service manuals should be coming in today so ill see what it says about replacement there.

[hinchcliffe]

Thanks, I'm off to purchase my manual now and copper plugs, TPS and crank sensor (for extra safety)

[strokeZ]

I changed all the TPS when I got new wheels and the tire company did have to initialize them in the computer through the OBDII port - then it took a few miles to clear the light ((!))

[Matt]

TPS = Throttle Position Sensor
TPMS = Tire Pressure Monitor System

Lol they have nothing in common.

[Matt]

However, since you mentioned it..... new TPMS sensors shouldn't have to be activated if they're the correct part number. I replaced all mine.... just ordered all new ones with my wheel/tire package and they were good to go. (Don't remember if I disconnected battery or not...)