P1391 AND P0123 combined on '98 5.2 L ram 1500 gasser

[Oliver]

Hi all,
i bought a black 4 door gen 2 badass it needs attention and care ;-)
i fixed brakes issues ...
i had an oxygen error code ... replaced, code fixed ... (exhaust converter has been emptied by previous owner ...)
i am messaging here this time because i got 2 codes combined ... -_-
it sounds like i should replace CMP (crankshaft sensor) and the TPS (trottle pos sensor ?)?
my engine runs smooth on low RPM, but as soon as i push gas .. trying to drive ...the engine runs very bad, makes bursts (translated by Google apologyse) when the engine is "very hot"; running since 30 mins .. everything goes good ... the truck runs very well ...
replacing all is a way of doing ... but this is not the smart way to work i think ...
is there someone witch could share experience with me here please ?

 

[Oliver]

sounds like it's a good question ? OR ... nobody understand me ?

 

[dudeman2009]

Just a lot of busy people.

First thing to do would be to check things out as you have already stated.

You can watch the RPM gauge, but a scan tool will have a better result. You want to put the truck in park or neutral when its hot. Then rev the engine from idle to 5000RPM smoothly. If it shakes or is unstable then you'll need a scan tool that can read live or real time data for the next part. You need to watch the TP% with a scantool. With the engine off, key in the run/on position, smoothly and slowly push the gas pedal to the floor. The sensor reading should increase smoothly from 17% something to 80-90% something (I can't remember exactly what it should be) If it jumps or is erratic, replace the TPS, if its smooth, the crankshaft position sensor may be to blame. But both the TPS and crank position sensor may need to be replaced.

Only buy quality replacement parts, cheap TPS may be bad right out of the box.

 

[Oliver]

back on subject,
i will try looking deeply about theses percents ... to improve my knowledge!
i finally replaced the oxygen sensors (because i had the related codes)

replaced the crackshaft sensor IT WAS HARD BUT I DID'NT remove the front Wheel or anything else ! except the exhaust plate .. to pass my arm ,
the plate below the distributor caps (the one with a small solenoïd)
- and the TPS.
NOW THE ENGINE RUNs SMOOTH, just like sweet music to my hears
sometimes ... it stops when i passes to LPG (Something like propane gas very comon here in the EU, due to gas price here ==> natural gas).

I play now with pipes for the exhaust system

THANK YOUUUUUUUU