clcam97

My car misfires at high RPM,by the way its a 97z,6M,my mods are,LT pacesetters,airfoil,MT drag radials,lt4 KM,SLP CAI,no cats,and 1.5 drop,i got 4 codes: 1 bad MAF,2 o2 sensor bank 2 i removed it cause the catalytic was removed also,3 EGR valve malfunction,and 4 canister malfunction. I bought my car 1 year ago and all of this time has been misfirering at high rpm,im doping one thing at the time, Should i go for a new MAF? Any help i will appreciate.

2QUIK6

Misfire at high rpms is usully caused by either weak coil, bad plug wire or plug wire connection, or bad opti.....if its a high mile opti, I'd look there first after checking the obvious plug wires. If you buy another and it doesn't cure the problem then you'll have a spare cause you will need it down the road sooner or later.
Maybe a bad ground would be another to look for, make sure all the grounds are connected at the back of the motor/heads.

2000GTP

What were the specific codes? As for the MAF, I would try cleaning the sensor itself first and then making sure the harness is corrosion free and not damaged before flipping the bill for a new one.

clcam97

i just put new spark plugs,and wires,i didnt get any codes involving the opti or coil,but that doesnt mean that they are malfunctioning right?

clcam97

The codes are:
PO100
PO160
PO400
P1441

BUBBA

If you have an AutoZone nearby, they will scan you pc and printout the codes and what they mean. Other places may do same. JMHO

Injuneer

To find out what the codes mean, do NOT accept the generic info from an auto parts store, or even many high end scanners. Use a list that is specific to the LT1, like the one Shoebox has here:

http://shbox.com/1/Dtcs.htm

To get a more detailed explanation of the codes, specific to your car, look here:

http://service.gm.com/gmspo/mode6/pd...c57P_F__yE.pdf

On the 97's, P0100 will often set because of a break in the wire feeding +12V to the MAF sensor. Check for the presence of +12V at the pink wire in the MAF harness connector.

P0400 will set if your EGR system has been disabled, or if your system is still functioning, but you are running an exhaust system with very low back pressure.

P0160 - When you removed the after-cat sensor, you should have installed an O2 "sim" to prevent the code, or had the codes programmed out of the PCM.

P1441 indicates the vacuum detection switch in the EVAP system is detecting a vacuum when the EVAP purge solenoid is supposed to be closed. May be the solenoid stuck open, may be a faulty vacuum switch, may mean the two hoses connected to the EVAP solenoid are switched and on the wrong connections.

clcam97

So my next question is,which one of those codes are more likely to be causing my car to misfire at high rpm's?

Injuneer

I'd say that P0100 is the most likely cause. If its misfiring, you should also have a code for a random misfire (P0300) or a cylinder-specific misfire code.