Intermittent cylinder misfire.

[marker1957]

I have replaced the following. Plugs, coil, plug wires, egr, crank position sensor, throttle position sensor, camshaft position, sensor fuel injectors. All 4 o2 sensors. It’s making me crazy. I’ve checked vacuumed hoses and double checked the plug gap. I may run for days with no problems then boom I can barely get home. I am still getting o2 sensor codes 2197 bank to lean. Not sure if they are related. Any advice? I’m desperate.

 

[CallMeSyd]

I have replaced the following. Plugs, coil, plug wires, egr, crank position sensor, throttle position sensor, camshaft position, sensor fuel injectors. All 4 o2 sensors. It’s making me crazy. I’ve checked vacuumed hoses and double checked the plug gap. I may run for days with no problems then boom I can barely get home. I am still getting o2 sensor codes 2197 bank to lean. Not sure if they are related. Any advice? I’m desperate.

Try unplugging maf sensor and see if there's any difference. Replaced fuel filter? Check fuel pressure.

 

[J_C]

I'd smoke test looking for vac leaks, like possibly upper intake manifold gasket. Could be a pain to find the cause with it so intermittent.

 

[marker1957]

Try unplugging maf sensor and see if there's any difference. Replaced fuel filter? Check fuel pressure.

I unplugged the map sensor and it ran bad until I plugged back in. Changed the fuel filter. Still no help Now it keeps going into fail safe mode. I’m stumped.

 

[J_C]

Hook up a scan tool capable of live data. Look at long term fuel trims. As stated above, you probably have an intake manifold leak, unless the scan tool shows misfires on the other bank as well (just not enough to set a trouble code), then might be a vac leak elsewhere.

 

[CallMeSyd]

I unplugged the map sensor and it ran bad until I plugged back in. Changed the fuel filter. Still no help Now it keeps going into fail safe mode. I’m stumped.

M.A.F. on the intake just beside the air filter box. And what he said ^ check your live feed on all sensors as well and verify throttle control values look like they should. I think it could be an intake/vacuum leak as well. You could try the old propane trick or ether to hunt for leaks, but your live data should tell you right away if it's running lean.

 

[TechGuru]

I'm confused, are we talking about a V6 or V8?

What plugs did you install?