system too lean bank 1 and 2

[Dcarlson5]

what could cause this?
My engine is running rough and the error code say system too lean bank 1 and system too lean bank 2
Also sometime it says misfire cylider 4 or random cylinder misfire but what is the cause of too lean?

[blazes9395]

What codes are you getting? What year is it?

[Dcarlson5]

Originally Posted by blazes9395

What codes are you getting? What year is it?

It is a 98 blazer 4 wd vin w

[BlazerLT]

Any other symptoms like pinging under load at all?

[Dcarlson5]

Originally Posted by BlazerLT

Any other symptoms like pinging under load at all?

No just knocks A little at first when it is started.
But when it gets to running it runs fine but idles alittle bit rough.

[ricksza]

Lean means too much air or not enough fuel. Check for a vacuum leak, clogged fuel filter or low fuel pressure.

[BlazerLT]

Knocking at startup means you are probably using a Fram oil filter.

Also, are you using 5w30 like the manual states?

[blazes9395]

A low fuel pressure can cause the little poppets at the end of the injector nozzles to not work properly and stick or not even open, causing a random cylinder misfire and a lean mixture.

[iamryn]

Originally Posted by BlazerLT

Any other symptoms like pinging under load at all?

My 5.7 Vortec in my 96 Sierra 3500 has the original problems of this guy with the pinging under load. But I'm only am lean on bank 2.

I replaced the intake gasket, and originally stuck the distributor in wrong got the 1394 code (I think, the cam/crank sensor corrolation problem), I got taht code gone, and it seemed to run fine (when in park), a slight ping when I backed off at 4000Rpms, but once I got on the road it seemed just as bad as before I got rid of the 1394 code. I can smell the fuel and watch the gas gauge go down, Im probably getting about half the usual MPG. I am going to check the Fuel pressure, the pressure regulator, and the MAF tommorow, but I figured I'd post up since you seem to know what might be causiing this and I can have something else ot check out. Thanks.

[ricksza]

Originally Posted by iamryn

My 5.7 Vortec in my 96 Sierra 3500 has the original problems of this guy with the pinging under load. But I'm only am lean on bank 2.

I replaced the intake gasket, and originally stuck the distributor in wrong got the 1394 code (I think, the cam/crank sensor corrolation problem), I got taht code gone, and it seemed to run fine (when in park), a slight ping when I backed off at 4000Rpms, but once I got on the road it seemed just as bad as before I got rid of the 1394 code. I can smell the fuel and watch the gas gauge go down, Im probably getting about half the usual MPG. I am going to check the Fuel pressure, the pressure regulator, and the MAF tommorow, but I figured I'd post up since you seem to know what might be causiing this and I can have something else ot check out. Thanks.

If your reading lean just on Bank 1, could just be a bad sensor. Fools the computer into thinking that it's lean and trying to richen up the mixture. Make sure that you verify the O2 Sensor operation. Will it read on the rich end? To check, with the engine running have the scanner hooked up and spray some carb cleaner down the intake. Both front O2 Sensors should bounce up near 1.00 volts as long as you're spraying.

[BlazerLT]

Originally Posted by iamryn

My 5.7 Vortec in my 96 Sierra 3500 has the original problems of this guy with the pinging under load. But I'm only am lean on bank 2.

I replaced the intake gasket, and originally stuck the distributor in wrong got the 1394 code (I think, the cam/crank sensor corrolation problem), I got taht code gone, and it seemed to run fine (when in park), a slight ping when I backed off at 4000Rpms, but once I got on the road it seemed just as bad as before I got rid of the 1394 code. I can smell the fuel and watch the gas gauge go down, Im probably getting about half the usual MPG. I am going to check the Fuel pressure, the pressure regulator, and the MAF tommorow, but I figured I'd post up since you seem to know what might be causiing this and I can have something else ot check out. Thanks.

Please post in the appropriate forum section.