I am not sure what you have done. But from the first thread I would start looking at CPS if this was my truck. A easy quick fix is just to unplug it and plug it back together.

This is the crank shaft position sender. the connector is located at the back of your engine on the Rt. side of your vavle cover if standing in front.

You wouldn't believe how many different problems this little booger can give you. If unpluging it and plugging it back it temporarily relieves your symptoms it may be time to replace it.

Here is a nice reference pic

 

I don't know if the CPS can account for the decreased fuel mileage over time, and then also for the sudden starting issues. I will look into it later, but the 46 psi coming off the fuel rail is my first concern.

On my year the pressure regulator is one unit with the pump inside of the gas tank. I am going to try talking to the jeep techs at the stealership to see what they say.

 

Yes it can account for the starting issue. The CPS can account for lots of different faults.

 

It doesnt suprise me about the start issue, but what about the fuel mileage and the issues concerning that? The fuel mileage is the bigger problem at this point. Can the CPS also cause the spiked fuel pressure.

 

It's ultra-rare to find high fuel pressure. I'm an electrical diagnostic- and driveability-tech, so basically all I see are the cars that others have given-up on. I've seen high fuel pressure cause issues twice in 18 years.

Basically, your PCM monitors the O2 sensors and can compensate quite a bit for changes in fuel pressure. The PCM can shorten the pulsewidth for the injectors to cover the extra couple of psi, no problem.

I think the gauge accuracy needs to be checked. Go to a Harbor Freight store and buy a fuel pressure test kit ($10) and an oil pressure test kit ($10). The only difference between these is the fittings. The actual gauges are identical. Test your pressure yourself with both gauges, then you can be for-sure about the fuel pressure.

The reason to buy the two different kits is so you can test other things with them later. The oil pressure kit does oil pressure, trans pressure, etc... the fuel pressure kit has several fittings for different vehicles.

 

I just went to the dealership and the mechanic there told me that 46 PSI is normal operating pressure for the fuel rail when running. Now I am back to square one.

Brings me back to the o2 sensors and the TB. I installed a bored TB maybe a month ago and for a while I have had the suspicion that the o2 sensors were going due to them having 105,000 miles on em.

 

ugh life just got harder.

It poped a code today, it was Po 432

According to the manuel it means Catalyst 2/1 efficiency below required level.

what in the world does that mean? can anyone shed light on this and maybe put it into context to the other issues ive been having?

 

bump anybody?

 

either Cat is bad or o2 sensors... some mechs have a gauge that plugs into the exhaust o2 sensor before the cat and meaure the amount of pressure to let you know if the Cat is bad or not... a dealer would have this... but the codes from one of them 2 things...

 

i would start there for your other issue now... maybe the cause and it just finally got bad enough to pop a code...

 

It has gotta be the o2 sensors, the cat is new, and it doesnt have any damage what so ever on it.

 

honestly and this is just what i think... I have never seen a o2 sensor stop a vehicle from running right... its always just a light on the dash and alittle less gas milage... Ive replaced several in my life (was nissan tech) and never ever ever have i ever seen one fix a vehicle from not running right... that just my thoughts though... either way you still should swap o2 sensors... there broke... and why not? never know...

 

Yea, well at this point ive gotten fed up and I cant seem to figure it all out. 02s are deff on the list but I plan on taking it to the dealer on tuesday and seeing if they can figure it out.