Chevrolet Repair: Truck leaning out, mass airflow sensor, chevrolet silverado

Question
Hi how are you I'm having trouble with my 05 Chevrolet silverado in has the 5.3 325. It is distributorless with a plastic intake. Just to let you know I have already replaced all the oxygen sensors, mass airflow sensor, gutted the cats, and replaced the spark plugs. The 02 sensors at one time were black now they are whitish not what I prefer. When I'm going down the road it will run perfect for about 5 miles then it will jerk then instantly run fine. Before changing out all that other stuff it was doing the same thing but backfiring. Its not burning any oil are anything but its leaning out apparently. I've sprayed carb cleaner around the intake to see if it has a bad gasket and the idle never changed so I'm stumped and agitated with it. sorry for making my list so long but I hope I gave you enough information.

Thanks Keith Gohlke


Answer
Hi Keith... do you have a scan tool... if you do put it on and watch the data stream and see what the o2 sensor readings are...if they in fact are running too lean you can buy a reprogrammer to program the computer to run where you want it to...because you cleaned out the cats you will have a lean problem...make sure computer goes into closed loop before taking readings...if a reprogrammer is not an option try running a colder thermostat as engine temp also controls lean/rich... as a matter of fact check the stat and temp sensors and make sure they are working right and you don't have one reading high and one reading low....hope this helps