No power doesnt Idle

P0340 code means "Something" is wrong in the timing...
from CMP (Camshaft Position sensor) to the crankshaft bolt.

Very first thing, verify connectors are clean and shiny.
clear all codes, even hard codes.

Could be clog catalytic converter.Tune up fuel filter,coils,air filter.

Here is the OBD2 emission system drive cycle test procedure.
Engine coolant temp must be below 70c (158f) before starting the engine for either the first or second trip
The fuel level should be less than 1/2 full
First trip:
Start engine, idle for at least 1.5 minutes
Drive 3 minutes, hold b/f schdl: 1.5-2.0 msec, selector lever "3rd" eng rpm 1,800-2,000 A/C switch:ON Hold the recommended b/f schdl range. Allow road speed to vary as necessary.
Drive at 55-65 mph for 1.5 min b/f schdl 2.0-3.2 msec, selector lever "5th" Engine rpm 2,200-3,000
IGN "off" for at least 10 seconds (not more than 5 min)
Dive at 50-60 mph for 3 minutes Selector lever "4th" keep engine speed above 3,000 rpm Allow speed to vary if necessary. Do not decelerate for more than 3 consecutive seconds. A/C switch ON.
Drive at a steady state cruise of 53-58mhp b/f schdl more than 1.8 msec selector lever "5th" eng rpm 2,400-2,600
Downshift to "4th" and decel more than 5 seconds without breaking, then idle for 1 minute.
Drive two minutes b/f schdl less than 2.0 msec Accelerate to 41 mph, decelerate to 34 mph, accelerate to 41mph. Do not completely release the accelerator. A/C switch off.
Idle 1 minute in park or neutral
Drive two minutes Steady state cruise at 31-44 mph. Selector lever "4th" A/C switch OFF. Hold the accelerator pedal as steady as possible. Allow speed to change if necessary.
End of first trip. Turn the key off the begin the second trip.
Second trip:
Start engine, idle for at least 1.5 minutes
Drive 3 minutes, hold b/f schdl: 1.5-2.0 msec, selector lever "3rd" eng rpm 1,800-2,000 A/C switch:ON Hold the recommended b/f schdl range. Allow road speed to vary as necessary.
Drive at 55-65 mph for 1.5 min b/f schdl 2.0-3.2 msec, selector lever "5th" Engine rpm 2,200-3,000
IGN "off" add four gallons of fuel
Dive at 50-60 mph for 3 minutes Selector lever "4th" keep engine speed above 3,000 rpm Allow speed to vary if necessary. Do not decelerate for more than 3 consecutive seconds. A/C switch ON.
Drive at a steady state cruise of 53-58mhp b/f schdl more than 1.8 msec selector lever "5th" eng rpm 2,400-2,600
Downshift to "4th" and decel more than 5 seconds without breaking, then idle for 1 minute.
Drive two minutes b/f schdl less than 2.0 msec Accelerate to 41 mph, decelerate to 34 mph, accelerate to 41mph. Do not completely release the accelerator. A/C switch off.
Idle 1 minute in park or neutral
Drive two minutes Steady state cruise at 31-44 mph. Selector lever "4th" A/C switch OFF. Hold the accelerator pedal as steady as possible. Allow speed to change if necessary. I especially like the part where they want you to add four gallons of fuel. Not three gallons, not five gallons, four gallons. Gotta love those Nissan engineers. ...and of course they state that if the trace is not followed exactly (i.e. you botch the acceleration/deceleration) you have to start all over again from scratch

Sounds like it needs to go through a drive cycle. After the computer has been deprived of power for ten or fifteen minutes, it will need to relearn the paramiters of the electronics for the engine. Take it on a 10-15 mile drive with out stops (the high way) at about 55-65 mph and it should be ok. If not you may other problems.

you may have a broken alternator belt or timing belt.

I had a similiar problem on my 1999 Dodge Ram 1500 Conversion Van. It ended up being a partial collapse of the catalytic converter which didn't allow adequate exhaust. The problem only showed itself because I could not get over 55 mph going up a small hill.

have fuel pump pressure checked 50-60 Psi at idle 60PSI with vac line diconnected from pressure regulator. If that checks out check for ingation switch failier may be keeps car power on but telling ecm that it has been turned from run. Also have a wave form done on fuel pump as it can still have good pressure but not be fully funtional elctricly. if you have acsses to a tech 2 have it checked for codes as it may not have turned on the light but may have stored a code

You sould have recieved a "recall" notice in the mail about the cruise control for fire and failure issues. they are adding a fusable link where the cruise control harness connects to the brake master cylinder. if you have not had the recall performed yet you should SERIOUSLY consider getting it done, mainly so it doesnt catch fire, but "could" be the result of the failure you've been experiancing! btw, almost ALL Ford vehicles have been affected with the cruise control recall. hope this helps!

all the sudden the check engine light came on and it started to idle funny and dying at stops. I had a diagnostic done on it and changed out the idle air control valve but it doent seem any different. and the check engine light is still throwing the same code. we adjusted the idle up so i could drive it with out it dying but it is still acting funny.