Well after replacing the engine (98 blazer VIN W) and many other components under the hood I developed another issue last week on my way home from work. When I went to pass a truck on the interstate...I accelerated and went to about 3100 RPM....I noticed the check engine light flashing and while not stumbling...the power seemed topped out. Backed off the accelerator and the engine light went on solid....remained that way for the rest of the trip. Pulled the code and found a P0300.
Next day I ran into work (about 30 minutes on InterState) with EFILive logging data and found I could reproduce the SES light by hard acceleration (Throttle position at 75 %) to 3000 RPM....The data logged showed that the misfire was occuring primarily on cylinder 1 (In fact that time the code was P0301) approx. 1500 misfires in 45 seconds. I also noticed the STFT jumps instatly to +20 % only on Bank 1...and the Advance was only about 19 - 20 degrees.
I've reproduced this about 10 times logging data and have the exact same results...9 out of 10 times it's a P0301...although I do see a small number of misfires on other cylinders.
Yesterday, after some research I changed the Coil, MAP sensor, fuel filter and cleaned the EGR...I then reset the Leared fuel mode. A Test drive now shows approx 1000 misfires on Cyl 2 on hard accerleration (3000 RPM) for approx 15 seconds. I reproduced this 5 times in a row...again with the STFT jumping to 20 % and back down to 0 when you let off the pedal, Advance was 20.5 degress when the MF occured. I'm not seeing misfires on any other Cylinders now.
The truck idles dead smooth and accelates smoothly with lots of power. I record no misfires as long as I don't hit 3000 RPMs
Here's what I've done
Yesterday
MAP sensor
Fuel Filter
Coil
500 miles ago
Reman GM engine
Radiator
Waterpump
O2 sensors
Wires
Plugs (Delco Plats)
Cleaned MAF
Cleaned Injectors and Intake (While off engine)
New GM distributor
9000 miles ago
Reman GM transmission
Fuel Pump
Starter
Anyone have any suggestions ? I could send some EFILive data if you tell me what attributes you want sampled.
Thanks
Mike