Rough idle after treatment.
 

Hello folks.
I'm new to the site and a recent buyer of a 2001 Camaro SS (SLP #3426) with 89000 miles. The car was a one owner, clean history car that sat more than driven in South Georgia. The original owner seemed to not have taken the best care of the car, but in pretty good shape. Mostly cosmetic from sitting in the hot sun. I'm a deputy and drive the Camaro on my days off. Since I purchased the car two months ago, I have only put 150 miles on the car. During that time, I went a little overboard and put two cans of Seafoam in the car, specifically gas tank treatment. Thinking I would give the car a little more help in cleaning the fuel system I put a whole bottle of Chevron with Techron in the tank. The tank was about three quarters full. The car truly ran good before doing all the treatments, I noticed a good idle and acceleration after the Seafoam treatment. Yesterday evening with approximately half a tank of gas I put the large bottle of Chevron in the tank, and let it sit for the night. Going to run errands this morning the car cranked great and idled great. 15 minutes into the drive I felt the car have a very brief burp and the check engine light came on. Now there's a slight rough idle. The code thrown by the motor is P0430 bank 2 (Catalyst System Efficiency Below Threshold Bank 2). Again the car was running fine until running the fuel treatments. I'm sure some will say, don't fix it if it's not broke, why the over kill on treatment. I run treatments all the time in my patrol cars and felt safe doing it to my Camaro. From what I have read I suspect now a dirty spark plug, dirty injectors, and/or the car is running too rich from running the fuel treatment due to too much treatment. Opinions and direction will be appreciated.

Re: Rough idle after treatment.
 

It sounds like the cat is clogged.All the stuff that was loosened with the cleaners may have settled there.From what I know the cat can be 5% clogged and throw a code( on my saturn vue it was).If you have 02 sensors one in front of and behind the cat I would have them checked first.Hope this helps.Also the fuel additives should be poured in an empty tank,then filled with gas as to dilute it up good.(10 gallons for a small bottle of techron ect.)I would change the fuel filter as well.Hope this helps.:)

Re: Rough idle after treatment.
 

Sometimes I wonder if Seafoam really is safe for the O2 sensors..... seems to cause as many problems as it cures, at least based on the posts I've seen here over the years. Also don't know if the LS1 fuel gauge suffers from the same inaccuracy as the ones in the LT1 cars, but if it is as inaccurate, 1/2 on the gauge could mean as little as 5 gallons in the tank.

Re: Rough idle after treatment.
 

Most cleaners available arenot really that strong. Unless you have some old GM top engine cleaner it probably didnt do anything. I would think it is just a coincidence. Start with the basics and fill the tank up. Don't overthink it and start spending money convinced it is cleaner related. K.I.S.S.

Re: Rough idle after treatment.
 

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