I don't drive the truck much and just filled it up again the other day from almost completely empty. For the last couple of days I've been telling myself "this thing is suddenly a dog". Could this percieved power loss be due to weaker winter gas and I just noticed it more this time since I filled up from nearly empty?

It's not a huge power loss but it did seem noticeably weaker one day. It is noticeably enough down on power I'm now asking myself if my Hughes plenum repair could have gone bad and I'm experiencing a plenum leak. I plan to do the plenum leak vacum test per the servicce bulletin when I get to it but figured I'd throw this question out for you forum gurus to chew on.

Another possible symptom is the sound: it just doesn't sound quite as gnarly for the last few days... almost a bit more subdued like I lost some compression points but this could be just some touchy feely BS.

Maybe I just need a tune up. These tune up parts have less than 10K miles though. They couldn't possibly be worn to the point of needing replacement after less than 10k miles could they?

Ideas please fellas. I'm fishing for ideas...

 

While possible it seems unlikely. The cat was brand new Mag hiflow 3" si/so I installed last spring some time. The engine has a couple thousand more miles since then but hasn't smoked from what I've seen.

 

how about ur cat?

 

How in the hell did my responcse get before your question?

 

idk its been doing this for a while. the only reason i said the cat is bc u think it got quiter

 

hmm. Yeah, sound change is hard to describe...not really quieter per se just mellower or less violent. Haha! probably completely meaningless but unfortunately I'm not the best communicator ever. More like a tone change than a volume change if that makes any sense.

 

So it seems like it might have been Arco gas slowing me down and not winter gas. I filled up with some Chevron gas tonight on the way home and my first impression is it made a pretty noticeable difference. When that happened it struck me maybe gas brand is the problem. 2 fills ago at Chevron power fine, 1 fill ago at Arco power lame, last fill at Chevron power seems to have returned. (?) I'll give it a day or two to make the final call but it sure seems like that might have been it.

Comments? Anybody else ever notice that Chevron gas is better than Arco gas?

 

Yep. I first noticed it in the late 1970's, in fact. Arco Premium (leaded!) would ping in my (built) 440 while neither Shell nor Chevron would.

 

Hmm, I wonder if the more expensive Chevron gas is a better deal due to being able to go farther on the same volume compared to lower cost but potentially less effective Arco fuel. I already can't go back to Arco with my truck since I now believe Chevron gas makes more power, but if I could also consider it a better "deal" then even when I'm poor I'd still have to go to the more expensive Chevron gas.

I wonder if:

1. It could really be true and,
2. its true across the board for all gas grades and consumer vehicle varieties
3 I've been a sucker all these years going to Arco for the "low cost" gas and it was actually costing me $$$$ the whole time

more study is needed

 

My mileage usually drops from 14 to 10 in the winter :/ i got a '01 5.9.