97 K1500 5.7L MT
147,000 miles
Got a p0300 a few days ago going uphill, no other codes. Nothing really noticeable with drivability.
Recent history:
Replaced old lower manifold intake gasket with metal-backed one in 2020.
Changed plugs, wires, cap and rotor in 2021. (AC Delco)
New fuel pump, tank and filter this past May when I had the bed off to paint the frame.
New Oil pressure sensor, distributor gasket to correct oil leak in August.
Another new Delco cap and dizzy holding bracket last month. Rear of previous cap was loose and threw off cam retard offset. Offset is currently +0.6
Some DashCommand screenshots from this afternoon. I know I'm probably missing some information.
Misfire counter and Fuel trims a minute or so after startup:
Two more after about 10-12 minutes. The STFT must not have registered digitally when I took the screenshot.
Other notes:
-Upstream O2 sensor on bank 1 has some chaffing on one of the wires. I swapped that sensor with bank 2, and didn't really notice a difference.
-Tried doing the propane vacuum leak test, no change anywhere.
-Cleaned the MAF sensor.
-Twice over the summer, the truck would be hard to start after filling the tank, but would eventually fire up. Pump is Delco and is new, as noted above.
-AFAIK, the injectors are the original spider injectors. I took the upper and lower manifold off as one unit when I did the lower gasket.
- I tested the ignition coil Ohm measurement with the test found in the service manual. Everything was within spec.
Again, I know I'm probably leaving things out, but if anyone could point me in the right direction, I'd appreciate it.
147,000 miles
Got a p0300 a few days ago going uphill, no other codes. Nothing really noticeable with drivability.
Recent history:
Replaced old lower manifold intake gasket with metal-backed one in 2020.
Changed plugs, wires, cap and rotor in 2021. (AC Delco)
New fuel pump, tank and filter this past May when I had the bed off to paint the frame.
New Oil pressure sensor, distributor gasket to correct oil leak in August.
Another new Delco cap and dizzy holding bracket last month. Rear of previous cap was loose and threw off cam retard offset. Offset is currently +0.6
Some DashCommand screenshots from this afternoon. I know I'm probably missing some information.
Misfire counter and Fuel trims a minute or so after startup:
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You must be registered for see images attach
You must be registered for see images attach
Two more after about 10-12 minutes. The STFT must not have registered digitally when I took the screenshot.
You must be registered for see images attach
You must be registered for see images attach
Other notes:
-Upstream O2 sensor on bank 1 has some chaffing on one of the wires. I swapped that sensor with bank 2, and didn't really notice a difference.
-Tried doing the propane vacuum leak test, no change anywhere.
-Cleaned the MAF sensor.
-Twice over the summer, the truck would be hard to start after filling the tank, but would eventually fire up. Pump is Delco and is new, as noted above.
-AFAIK, the injectors are the original spider injectors. I took the upper and lower manifold off as one unit when I did the lower gasket.
- I tested the ignition coil Ohm measurement with the test found in the service manual. Everything was within spec.
Again, I know I'm probably leaving things out, but if anyone could point me in the right direction, I'd appreciate it.
Last edited: