Someone please help!!

Noticed one day after fuel tank almost on empty, filled it up, next day,my jgc `99 started misfiring when cold.Check engine light came on and said p0700.transmission won't shift out of 3rd gear.Thought it was the fuel filter clogged,cleaned out the tank,changed spark plugs,even changed the fuel pump(cost me a fortune as i live in africa and not readily available jeep spare parts here).Nothing changed and now even gives me p0523(oil pressure high voltage).Someone please help as i dont know what it could be..!!!

Is the Transmission shifting out of 3rd gear? if it is it could be a false code, they will do that once in a while. The transmisssion trouble is usally related to a solenoid if it is not shifting out of 3rd gear. A Trans fluid and filter wouldnt hurt if you have to go in. The oil pressure code is usally abad sending unit, make sure the wires are in good contition first a lot of sensor trouble is related to bad wirring - breaks and shorts.
You should clear the codes if you dont have a ScanTool Remove the negative Batterry Cable for about a minute. If the codes keep comming back you will have to do further Diagnostics. If You have a switch on the dash for the overdrive make sure it is turned off.

Is the Transmission shifting out of 3rd gear? if it is it could be a false code, they will do that once in a while. The transmisssion trouble is usally related to a solenoid if it is not shifting out of 3rd gear. A Trans fluid and filter wouldnt hurt if you have to go in. The oil pressure code is usally abad sending unit, make sure the wires are in good contition first a lot of sensor trouble is related to bad wirring - breaks and shorts.
You should clear the codes if you dont have a ScanTool Remove the negative Batterry Cable for about a minute. If the codes keep comming back you will have to do further Diagnostics. If You have a switch on the dash for the overdrive make sure it is turned off.

Thanks for the info, it was a big help disconnecting the battery terminal!It got rid of all faulty codes, but the car still misfires,and the only code now is p0700.And no,it still doesnt shift out of 3rd.You think it could be the ignition coil too?input/output sensor?I have to order these parts from south africa and it takes a week to get them up here. Will also change the ftransmission filter and oil.My car has only 64000kms on it.Why does it misfire??arrrgghh!!

Iam not sure why it is missing, first thing I would try is to check the plugs and wires. Try spraying water at night on the wires and Ignition coil to see if there is any arcing. Just a spray bottle that people use for plants. I hate to see you buy a coil without needing one especially at the prices over where you are.The trans not shifting out of third gear is couldbe a few things.Check the fuse for the overdrive circuit, the overdrive solenoid shorted. Fluid level and fluid conditiion has alot to do with operation. Could be a few other things too. Getting back to the engine missfiring when you ran low on gas could have picked up some dirt and might be affecting one or more of the fuel injectors. Just a Guess.

Iam not sure why it is missing, first thing I would try is to check the plugs and wires. Try spraying water at night on the wires and Ignition coil to see if there is any arcing. Just a spray bottle that people use for plants. I hate to see you buy a coil without needing one especially at the prices over where you are.The trans not shifting out of third gear is couldbe a few things.Check the fuse for the overdrive circuit, the overdrive solenoid shorted. Fluid level and fluid conditiion has alot to do with operation. Could be a few other things too. Getting back to the engine missfiring when you ran low on gas could have picked up some dirt and might be affecting one or more of the fuel injectors. Just a Guess.

Thanks for the tips. What i did this morning was, with the car engine running,pulled out each coil at a time.Seems like 2 coils not sending enough power - which leads me to believe it could be 2 coils. possible?a coil costs me about 150us$!!regarding transmission, fluid seems to be clean and levelled.But will change anyway as per your opinion.Thinking of replacing the i/o sensors on it.150 us$ each as well!!Checked for shorts and fuses. all fine.just let me know if normal to have 2 coils not sending enough power at 65000kms.taking it step by step..

Dont know if the Trans fluid and filter will help, Jeep transmissions are very touchy about fluid level and condition. If that dosent help the Sensor that might be the trouble is under the3-4 uccumulator housing. Really need a manual too get a good picture. Mine is a 96 not sure if it is the same as a 99. You might try online parts dealers some will ship anywhere much cheaper than the South Africa dealers. The coil packs are tricky to detect without a scan tool, check the ohm readings and see if there is any variations. Hope this helps post back if you need more info.

Dont know if the Trans fluid and filter will help, Jeep transmissions are very touchy about fluid level and condition. If that dosent help the Sensor that might be the trouble is under the3-4 uccumulator housing. Really need a manual too get a good picture. Mine is a 96 not sure if it is the same as a 99. You might try online parts dealers some will ship anywhere much cheaper than the South Africa dealers. The coil packs are tricky to detect without a scan tool, check the ohm readings and see if there is any variations. Hope this helps post back if you need more info.
Hey there!!

You were absolutely right!!Cleaned the injectors and the engine is running smooth as silk!!!However, the check engine light still gives me the p0700 code and doesnt shift out of 3rd gear.If it wasnt for u , i would never have messed with the injectors!!got 1 problem out of the way.bloody p0700 still baffling me....!!Sensors????????

Got my sensors,put them on, and voila!!Bye bye check engine,transmission brand new!!!cheers!!

Good Going! Hope they didnt rob you too much for parts. If you need parts again try E-Bay some of the dealers ship about anywhere.