So my car turned off while at a stop, and my check engine came on. I changed out the camshaft position sensor and the crankshaft position sensor aswell. But the problem still persists. Ive noticed the car idles very low like around 500rpms then it stalls out. I was wondering could it be that my car is running lean? I did recently install a z1 plenum spacer. The car already had an injen cold air intake, test pipes and a full exhaust. All these but i havent tuned it nor changed the fuel injectors. Could that be causing it to stall or idle so low?

 

Are you getting any codes?

 

Like Spike said you definitely want to invest in a code-reader. You didn't mess with the throttle body when you did the plenum spacer did you? They can be incredibly temperamental.

 

Pretty much any auto store can read the code for free if you can get your car there. Not likely anything to do with running lean considering your mods. You will not need bigger injectors with those mods, just a tune.

There are 2 camshaft sensors for DE (only intake cams) and 4 for revup/HR (intake and exhaust cams). Did you change them all?

 

Idle relearn procedure might be in order. Personally I would reset the ECU, without a code scanner the simplest method is just unplugging the battery for a while. If you put a plenum spacer on, you could also have a vacuum leak or rogue air issue. Double check all the plumbing connecting to the intake. Also make sure your MAF sensor plug has a solid connection. I assume you unplugged and removed all the stuff when you installed the plenum spacer. MAF sensors are very touchy, I would personally disconnect the battery before touching the MAF plug. As a last resort you can try cleaning the MAF sensor using one of the appropriate MAF cleaning products, usually this is not recommended because it can often times cause an issue when none existed before.

Another possible culprit could be the test pipes. If you deleted your CATs, then your O2 sensors might be getting bad/unexpected readings. This can and does cause your ECU to mess with the Air/Fuel ratio trim levels. An out of spec reading on the downstream O2 sensors should be giving you a Check Engine Light (CEL). What kind of test pipes are you running? The Motordyne ART pipes seem to be the most reliable test pipes in terms of preventing the O2 sensors from tripping a code, but it's not guaranteed.

Fuel injectors shouldn't cause this issue, if there was a problem with them you would get getting misfire codes and your engine would be running very poorly with noticeable power loss.
-Icer

 

as mentioned above, start with the ECU reset and then a TB relearn. If neither of those work, start checking for vacuum leaks around the plenum and if you installed a PCV valve, check the joints and the hose that goes into the block for cracks. It's rather important to follow the re tightening procedure on the plenum to the T, if that didn't occur, it would bring validity to a possible vacuum leak. In my opinion stay away from cleaning the MAF. Very few times does this actually remedy anything and i found that after cleaning them, the fuse is lit for it to fail. They work better just left alone until they fail, then replace with OEM.