Truck takes a while to crank, idles up and down until the temp. rises, dies often, seems to "bog" down when I accelerate, and horrible fuel economy. I brought it to autozone and they ran a diagnostics on it codes are : P0123, P1492, P0107, P1296. I've changed the IAC and the TPS, any ideas? Next I figure I'll be changing the MAP. BTW Its a 1999 1500 5.2L, 152k miles.

 

p0123 is a TPS code. voltage too high. (tps bad or possible short to 12v)
p0107 is MAP sensor voltage too high.
P1296 No 5 Volts To MAP Sensor
P1492 Battery Temperature Sensor Voltage Too High. i didn't know we had a battery temp sensor...

has the pcm been reset lately? i might reset pcm and see if they all come back or not. reset pcm by disconnecting negative battery cable and turning on headlights for 30 seconds.

any damage to wiring harness around throttle body? mice/squirrels?
w/o anything else to go on i'd probably replace map sensor, however, it doesn't go bad very often and its not a common problem. i think its not a cheap as the tps or iac..
i might check voltages at these sensors. you might have a short allowing 12 volt on those 5 volt sensors.

 

IIRC, a MAP sensor from an auto parts store will run you not very far under $100. Not quite as cheap as IACs or TPSs.

If the codes come back after a reset, replace the MAP. If still having the same code after that, dhvaughan probably has the right idea with the short in the wiring.

 

I'll try reseting it tomorrow at work, as far as the wires go everything looks good. Also I'll prob. go ahead and check the voltage at the sensors. Thanks for the help guys.