Seafoam is a useless gimmick and does not work well. I used it and it………..just made a bunch of smoke. If you want smoke, this is the crap for you!

When I got the new H2, I used Shell gas and it killed my cats by plugging the. Changed cats, and now use exclusively Chevron withTechron for the last decade. No more problems. No Seafoam or other crap additives go into my baby.

Throw a bottle or 2 of Techron concentrate into the gastank and vrooom!

For the other guy on this thread: Not all top tier gas is the same. Different additives. Some are better than others, so you can not generalize.

IMHO

 

Hey old senior guy finally, that was not me. My comment addressed Chevron gas stations having Techron as an additive to their gasoline, so it's possibly cheaper than adding Techron separately. I'm very big on Techron. To your other comment, I think Seafoam is a good product, albeit perhaps mild. Sorry you got black exhaust out of your car but I'm sure it was not the Seafoam. Been running it in a SeaRay 260, a 77 Pontiac Can Am, a 2019 XT5, a 2001 Vette, and an 04 Trailblazer with no issues whatsoever. To each his own.

 

 

Usually, if you see those two at the same time its a vacuum leak. Unless you got a batch of really really bad gas. But likely a vacuum leak. that being said seafoam in the gas wont hurt it. But for cleaning injectors you have to put it in the gas. If it is injectors you'll likely need to just get them professionally cleaned and tested. Or yank them and test them yourself. I'd start with a vacuum leak though. Very common on a car this old.