Hello I have a 1999 Chevy Blazer with a 4.3L I keep getting the code Multiple misfire or misfire cyl 5. I have replaced the crank sensor, cam sensor, ignition module, map sensor, injectors, fuel filter, fuel pump, plugs, wires, cap and rotor. The thing still idles rough, jumps and jerks while driving. Help Please

SOURCE: 2000 CHevy Silverado misfire code

try also the knock sensor..computer cant adjust timing

SOURCE: 1997 k1500 5.7l po303 misfire on cylider 3 ...

could be fuel injectors flooding cilinder fuelregulator not working right there is new up gradeinjector system

SOURCE: 99 chevy 1500 5.7 missing on 3 4 6 replaced tp,

Not much else it could be you have renewed just about everything. How about the coil sets? How healthy do the sparks look? try swapping some the faulty cylinder coils around with those that are good and noting the shift in misfires. The coils get hot and suffer over time. I think if you examine the sparks from each plug in turn you will see big differences from good to poor. For safety disconnect the fuel pump relay when checking the spark we don't want any fires.

SOURCE: 1997 Chevy k1500 idles rough #5 cylinder misfire.

soulds like time to run compression check

Jeffrey Turcotte

• 8991 Answers
• Posted on Sep 10, 2011

SOURCE: 1997 chevy 7.4 l has

Hi, if the code returns after replacing the sensor, odds are the wiring is the problem. Check the wiring and the connector for corrosion. Test the sensor to make sure it is getting the 5 volt reference signal from the computer. Test procedures are listed below. If the sensor passes at these tests, odds are the signal on the blue wire is not getting back to the computer.

TESTING

See Figures 2, 3 and 4

1. Backprobe with a high impedance voltmeter at TPS terminals A and B.
2. With the key ON and engine off, the voltmeter reading should be approximately 5.0 volts.
3. If the voltage is not as specified, either the wiring to the TPS or the ECM may be faulty. Correct any wiring or ECM faults before continuing test.
4. Backprobe with a high impedance voltmeter at terminals C and B.
5. With the key ON and engine off and the throttle closed, the TPS voltage should be approximately 0.5-1.2 volts.
6. Verify that the TPS voltage increases or decreases smoothly as the throttle is opened or closed. Make sure to open and close the throttle very slowly in order to detect any abnormalities in the TPS voltage reading.
7. If the sensor voltage is not as specified, replace the sensor.

Fig. Fig. 2: Using a DVOM, backprobe terminals A and B of the TPS sensor to check for proper reference voltage

Fig. Fig. 3: Using the DVOM, backprobe terminals C and B of the TPS sensor, open and close the throttle and make sure the voltage changes smoothly

Fig. Fig. 4: Throttle Position Sensor (TPS) wiring diagram