New Member....
 

Hi everybody....
Mostly,I have no problem with the mileage I get from my vehicles...I have a Kia Rio which gets a constant 50mpg,my Mazda truck gets around 33 mpg,but my motorhome,which I bought recently,is driving me a little nuts...

Its an oldie,an'84 Vanguard,with a GMC 350 motor...My previous campervan had the same motor,and I was able to squeeze about 17mpg out of it.This motorhome is bigger and heavier,and I didn't expect the same,but it only gets 10mpg...I have installed a K&N air filter,changed the plugs,cleaned out the carb,the tire pressures are up to spec,and I'm not driving it fast...any more suggestions..???

Cueball...

To move a large mtr home you may have a much higher FD. Changing it will be a problem because you need it to get up hills accelerate and such.

Take it to the emissions testing place and make sure it looks like the A/F ratios are right? Not sure if that really gives you much information...

you said it was heavier, but with the same engine, so it's most likely geared lower, so the engine reves higher, and there goes your mileage.
it's going to be hard without re-gearing your motorhome, and loosing alot of weight.
what kind of diesel would fit in there? they are a simpler engine, so it should be an easy swap that should give your more power, and better economy.

Thanks for the comments,guys....I'll definitely check the ignition timing...I might change out the oil too,for a lighter grade...will check manual first.It was changed at the dealers,but I have no idea what grade/quality it might be.

Putting the stock air filter back in isn't an option,I have K&N filters in everything,with more power and better mileage,although I know that on some motors the jetting needs to be changed.I did the same with my previous van,and it got an extra 2mpg just by changing the filter.I may fit a tach next,so I can monitor the idle speed,etc.

Putting a diesel in would be a great idea,but expensive....if I happen to blow up this motor,it will be the next step,though.

I never considered the gearing.Again,an expensive fix...see above,if I blow the trannie and rear end....lol

I'll double check the state of the carb for idle and mixture,too...

Thanks again for your help...any other comments will be most welcome

cueball...