Redline Si-1 turning the light out

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485
Location
IL
Thread starter
2005 Corolla, 299,000 miles. Bought new, have maintained it well, but never used fuel additives. It does NOT get top-tier gas 95% of the time. Around 270,000 miles the check engine light came on and it began idling really rough. Short on time at that point so I poured a full bottle of Si1 in from O'reilley's. After 3/4 of a tank, the light went out and it was running smooth. Now, 30k miles and almost two years later, same exact thing...in a half-tank, the light is out and is running smooth. These are the only two times I've used fuel cleaner in this car.
 

MolaKule

Staff member
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21,321
Location
Iowegia - USA
It could be a number of things but a computer scan should get you close to the answer. I had the same thing happen on our former 2008 TrailBlazer after using PEA/solvent-based cleaners and it usually happened during winter. I replaced the O2 sensors and the problem vanished. So you could have some flaky sensors or a partially plugged CAT. But I doubt the SI-1 is causing your problem, but rather trying to clean out a pre-existing or a marginal sensor problem
 
Messages
2,619
Location
High Tax Illinois
Why not Top Tier Gas? Here in my town Citgo, Phillips 66 and Casey's are all the same price. Citgo and Phillips 66 are TT fuel so that's what my cars get. Every 5th or so tank I put some Techron fuel cleaner in. Most any auto parts always have a sale on it.
 
Messages
820
Location
Upper midwest
Originally Posted by oldhp
Why not Top Tier Gas? Here in my town Citgo, Phillips 66 and Casey's are all the same price. Citgo and Phillips 66 are TT fuel so that's what my cars get. Every 5th or so tank I put some Techron fuel cleaner in. Most any auto parts always have a sale on it.
Your wasting your money adding Techron that often, you are using TopTeir gas mind you. Bi-yearly makes far more sense.
 
Messages
485
Location
IL
Thread starter
Odometer—yep. Code—didn't pull. I suspect you're right about a sensor, but as long as a $15 bottle makes it go away for another 30k, I'll put off investing more time or money. (On this car anyway)...on our other vehicles, I'd fix the issue. Top-tier—the location is just inconvenient for us. It's a time issue and not cost. Rural area, limited options. We put on over 70,000 miles per year across the household's vehicles, and this is the first issue that is POSSIBLY even related to fuel...and it first occurred at 270k....and all cars running non-TT fuel 95% of the time.
 
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