Slightly off-topic but I'll throw in my $0.02 here.
I've just spent a total of 8 hours at my local wrench trying to diagnose a "random mis-fire" in my 2005 5cyl Chevy Colorado 4x4.
We scanned for codes, got only one, did a "smoke test" for vacuum leaks, and finally a leak down test on the cylinder with the lowest reading (180 vs 190) to find I have very positive crankcase ventilation :eek2:
The Big Giant Brains (myself included) decided that my #1 cylinder was egg-shaped or all the piston rings had lined up - either scenario was not very palatable and the cure was NOT going to be cheap.
As luck would have it, a former co-worker drove in for a visit with the wrench (we all worked at a Ford dealer together a few years back). He had the same vehicle as I, with the same motor, and experienced a catastrophic motor failure at 7K miles that was being handled by Chevrolet warranty.
He was visiting with the technician that was swapping out his motor and while there took a peek at the internals of his, now dead, unit. What he saw was that his piston rings had become stuck inside the grooves of the #1 piston (unrelated to the motor failure) due to some "unknown gummy ch1t" in the grooves.
The Chevrolet tech related that he sees this condition a lot when folks continually run "cheap gas" from 2nd tier retailers in newer vehicles. The suppliers to these 2nd tier retailers usually put some sort of additive in the fuel before it leaves the distributor for the specific purpose of making the fuel palatable to much older vehicles.
My former co-worker was just as guilty as I was of buying the cheapest gas possible for our trucks. I have been buying from the local Thrifty Gas (an ARCO/BP subordinate) station since I landed back in SoCA last October.
At $4.25/per it was keeping me from going broke as I commuted 80 miles RT to my temp job. It was also, apparently, gluing the rings to the insides of the grooves in my pistons - with the #1 hole being the worst offender of the 5.
Prevailing wisdom now told us that I recently bought a tank of ch1tty fuel and that $200+/- of Chevron Mid-Grade with Techron and a couple bottles of Lucas Fuel System Conditioner "should" eventually clear the misfires and codes from my 96,000 mile motor.
Time will tell.......... :dunno2:
Moral of the story: run anything that you want/like in your moto - just know that if you buy from cheaper "off-brand" stations you will eventually pay the price (pardon the pun).
Run a tank, or two, of 1st tier premium every now and then and/or head to Pep Boys and pick up a bottle of Techron additive and do what J O does as preventive maintenance.
YMMV
