Grumpy needs your help. For quite some time Grumpy has set the P0302 (Cylinder 2 Misfire) code. Usually misfire codes are due to dirty injectors/sticky poppets. I've done Seafoam and the GM Fuel System Treatment Plus, to no avail. Since the injector/poppet is usually the cause, I decided to swap the injector for cylinder 2 with another cylinder. This in theory should move the misfire to another cylinder, if the injector is indeed the problem. Having completed the swap between cylinder 2 and 4, Grumpy still sets code for cylinder 2. Using the ScanGaugeII, I have discovered that if I don't let the throttle position sensor (TPS) hit 0 the code won't set. Playing with that idea I adjusted the idle to roughly 1000 RPM. Yeah, the van idles at 25 mph. Driving around, I see the computer recalculates where TPS 0 is and despite the much higher idle the code will set. However still, if I don't let the TPS hit 0 the code doesn't set. Anyone with GM experience have any ideas?

Here's a list of causes for P0302 errors and if I've done something about it:
* Faulty spark plug or wire - New installed
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector - Moved injector to different cylinder
* Burned exhaust valve
* Faulty catalytic converter(s) - Exhaust does not smell like rotten eggs
* Running out of fuel - Fuel pressure is good
* Poor compression - Wife hasn't reported smelling burnt oil after following the van.
* Defective computer

It maybe the O2 sesnsor..with 300,000 miles I would say it is ready...

A new wire could be faulty, or the plug broken, bad cap connection, etc etc....Try swapping wires on that cylinder

Swapped the cap and rotor from Green into Grumpy yesterday, no change.

Went to emissions to fail anyway, stupid emissions.

I'll borrow Green's oxygen sensor tonight and see if that helps.