engine problem....PLEASE HELP

my 96' blazer 4.3 is having some engine problems...been rev-ing up when u start it..then dropping back down...then back and forth...

feels like it wants to stull when u jump in and go....

stopped my autozone...they ran the codes.....there was 4

1 o2 sensor2 camshaft position sensor3 evaporative emission control system4 bank 2 fuel contol shifted lean

any suggestion on which one might be starting the problem?...the dude that worked there said that 1 was probally causing the others...

you sure it aint the crankshaft posisition sensor?

Originally posted by railmaster



you sure it aint the crankshaft posisition sensor?

yep.thats what it says on the little paper they gave to me

oxygen sensor

Edited: 1/10/2006 12:57:48 PM by LaidOutDawg

If the 02 sensor is bad, it will cause the evaporative emissions control and the fuel control shifted lean problems that are also listed. as for the crankshaft sensor, im not sure. Replace the 02 sensor first, then run the codes again and see if it got rid of problems 1,3, and 4. the o2 sensor tells the fuel system if it is pumpin too much fuel, if its bad, it will make the truck run rough. The o2 sensor also tells the computer if the cat convertor is functioning properly. hope this helps man,,, always start with the cheapest problem 1st. the crankshaft sensor I believe, helps the computer keep the ignition timing right, if that sensor is bad, it will throw the timing off.

yeah try replacing the 02 sensor first,they make fix all you problems

is it the vortec 4.3?

Originally posted by 2bad4ya



is it the vortec 4.3?

yes

yeah i would try and change out the o2 sensor first,the o2 senor ,when goes bad,starts a chain reaction with the motor,happened to my cuz's blazer,same make and model but his was 4wd

since the os is going bad,the camshaft position sensor,has to retard it self or advance its self for the o2 being bad,so it won't cause detonation,or thats what i have been told,i could be wrong