dirty fuel tank

[TheEmissary]

I have recently pulled my plugs, and noticed that reddish-tan deposits (rust colored) are present. At the same time, I pulled the plugs on my mom's 1978 Cutlass Supreme, and the insulator was a light gray, with some tan deposits.

From what I have seen on my plugs, I might have a dirty fuel tank. Are there any chemicals that can dissolve the dirt out of the tank, or do I have to consider replacing the fuel tank with a new one? I have replaced 10 fuel filters (carb inlet), and have used STP several times. So far, there has been no improvement. Last summer, I used to average 12.0 MPG, only to end up with 10 this year.

The Emissary
1981 K5 Blazer 4 x 4
305 (LE9)/THM350C/NP208

Other vehicles:
1975 Nova

 

[Waxer]

If it is in fact a dirty tank, you can pull it yourself and take it to a radiator shop. they can clean it out for you at a good price. Hope this helps

 

[getsome]

When I first bought my 1970 Cutlass it had been sitting for about 12 years with some gas in it and the tank was real rusty. I found this out by replacing the filter one day and knocking out dip sized pieces of rust. I replaced the filter every week untill I pulled the tank and had the thing cleaned and sealed. I think the sealer stuff is called Cream and it two parts. It's also used for bike tanks. It's been seven years now and I only replace the filter every six months or so. If I was going to do it again though I just get a new one. The differance in price was about 100 bucks.

Getsome