Question about 1999 Chevrolet Silverado 1500
I tow a 6000 camper trailer, and for my first outing this season on flat ground was getting about 5 mpg. Over past years, in the mountains I typically get 8-12 when towing, so I was very surprised how low this was. I am thinking of changing the O2 sensors to try that first. Any advice on what I could try, or how to try to diagnose this?
It is a K1500 5.7L with about 80,000 miles
I would do the usual tune-up stuff first.. plugs, wires, cap, rotor, filters, PCV valve, etc. Try to avoid aftermarket parts if possible. You may pay a little more for OEM GM / ACDELCO parts, but my past experience showed me it's not worth the aggravation.
I'm guessing this is a TBI. The throttle body may be getting gummed up. This is a pretty common issue with the 4.3 & 5.0 / 5.7's. Even the thirsty big blocks were prone to this. Pick yourself up a base gasket while you're at it, and a can of "Berkible 2+2 gum cutter". Wear rubber gloves when using this stuff (don't worry, it's "sensor safe"). Remove the throttle body and when you turn it over, you'll be surprised at the carbon build-up in all of the passages, etc, and how much better it will run afterwards.
Check for cracked / dry rotted vacuum lines too while you have it all apart.
I'm actually surprised you were getting the mileage you were (8-12), considering it's a 350, and the weight of the camper.
Posted on Jul 22, 2008
I have very poor gas gas mileage in my 1997 s10 truck .but the truck runs good, but it only get about 10 miles per gallon.
Posted on Apr 08, 2013
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Posted on Jan 02, 2017
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Apr 11, 2013 | Cars & Trucks
Jul 05, 2012 | 2005 Chevrolet Silverado
Mar 02, 2011 | 1999 Chevrolet Silverado 2500
4 way flat molded connectors allow basic hookup for three lighting functions; right turn signal / stop light (green), left turn signal / stop light (yellow), taillight / license / side marker (brown) and a ground (white).
4 way tow vehicle side.
4 way trailer side.
5 Way Systems
Same as 4 way system listed above but adds a extra blue wire for brake signal or auxiliary power. Used on pop up camper trailers or utility / boat trailers.
5 way tow vehicle side.
5 way trailer side.
6 Way System, Rectangle Plug 3/4 inch by 1 inch 6 way rectangle connectors right turn signal (green), left turn signal (yellow), taillight (brown), ground (white). The red and blue wire can be used for brake control or auxiliary. Use on a small motorcycle trailer, snowmobile trailer or utility trailer. Can also be used as custom wiring on trailers with 3 light/wire systems. See "Tow Vehicle Taillight Wiring" below.
6 way tow vehicle side.
6 way trailer side.
6 Way Systems, Round Plug
Round 1 1/4" diameter metal connector allows 1 or 2 additional wiring and lighting functions such as back up lights, auxiliary 12v power or electric brakes. Note: The black (sometimes red) 12v and blue electric brakes wire may need to be reversed to suit the trailer. Check with a test light or VOM. Uses: horse trailer, travel trailers, landscaping trailer, car trailer, etc.
6 way tow vehicle side.
6 way trailer side.
7 Way Systems
Round 2" diameter connector allows additional pin for auxiliary 12 volt power or backup lights. Uses: heavy duty landscaping trailer, car trailer, boat trailers, horse trailer, travel trailer, construction trailer, etc. Check with a test light or VOM.
7 way RV flat blade tow vehicle side.
7 way RV flat blade trailer side.
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