Bought a 2000 1500 with a 4.8l auto,check engine light keeps coming on... low cat efficiency,knock sensor,egr codes all set at the same time.... Broken wire supplying all these sensors? Have replaced cats and all O2 sensors ,egr valve and alt....

Truck is hard on fuel,even after codes are cleared... Sometimes light will stay out for a couple days,sometimes it comes on numerous times per day...

Truck has a K&N filter in it,otherwise stock, 190,00 miles...

Help??

Will any of the tuners help with mileage?

thanx rick..

 

sounds like you need to start doing some actual testing when the truck is acting up, and the only thing in common for those is the PCM.

Is the truck running rough?

 

Is it possible that all of those sensors share a ground somewhere?

 

My 99 just started with a few of those also. The catalyst low efficiency, and the Knock sensor bank 2
I figured with 170k on the clock, and 11 years on everything some stuff is bound to go bad. I got 2 new O2 sensors waiting to go in, and rounding up a couple of Knock sensors to replace the old ones.

I know when the PCM picks up the code for the knock sensor, it will max out KR (knock retard) but as soon as I clear the DTC, it goes back to normal. I dont have cats on my truck, and thought I killed all the DTC codes, but guess I missed the catalyst efficiency one??? Either that, or I got a bad O2 sensor.
I turned off the codes for and deleted my EGR, so its possible I would be throwing that one too??

Did you have your DTCs cleared after replacing parts?

Also, yes, almost any decent tune will help better your efficiency. What type of mileage are you getting now?

My '08 4.8 CC gets about 15, and my '99 RC gets about 17-18

 

BTW the bad mileage is more than likely caused by the Catalyst efficiency code. Wonder if its throwing the PCM into open loop and dumping fuel?

(yes Im being a post *****. Wonder if Ill break 5k tonight? )

 

I bought a cheapy code reader and clear the codes all the time....
It runs the same whether the light is on or not....

and it sets all 3 codes at the same time,does it more often when driving hard... maybe engine torqing more flexing a broken wire?

I was thinking common .5 volt feed wire or gound wire....

Not near as good on fuel as my old 2000 with the 5.3 in it... 15 highway on a good day... reg cab long box...

rick...