For medical reasons (wife)  I can't use my 2003 little tiny Class C with a 5.4 engine in it.  Parked since about 2016. 

I start engine and the generator once a month, get some oil splashed around and charge the batteries.  I add a fresh gallon of gas about every other month which brings the tank just about full.  Last couple months feels like a miss in the engine,  do you think it's okay if I were to idle it more let's say maybe 35 45 minutes and at a higher RPM than idling speed would hurt anything?

I let the license and insurance lapse being is just being parked for now, so can't take it on the street for a proper exercising.  I also add gas treatment when I add that gallon of gas to it. So I don't think it's bad gas.  Would running at about 3500 or 4,000 RPMs cause any damage,  to see if I can blow some junk out of it?  This thing loves to eat coilover plugs but the Miss now is not as rough as any bad coil over plug.

 

Added... no codes.  Fuel filter 4 or 5 yrs old. But only 3 tanks of gas thru it.

Remove the dog house and inspect for rodent damage; they love to eat vacuum lines and wires.  High idle no more than 2k RPM.  

How much fuel additive do you add each time with the gallon of gas?  How big is the fuel tank? 

Can you pump out all the fuel in the tank, say 5gal. at a time, burning the old fuel in the car then fill then fill the RV with fresh?  

You would be better off draining the fuel tank and fuel system. You'll fight long term storage of gas. 

 

Like all the gas powered fire trucks we have have issues sitting in a shed for months at a time. There is no amount of fuel additive that will keep it fresh. 

 

I rebuilt a carb on our old 1972 Ford F550 structure truck. Again fuel additives used but the carb went toes up fast. One reason we been ditching all our gas powered equipment and trucks and switching to diesel powered way less issues with long term storage of diesel fuel.

 

Now I can say without a doubt I've got a 55 gallon drum I keep gasoline in. As long as the bung cap is tight and sealed gas will last forever. Last time I filled the barrel was 5 to 6 years ago. Still fresh. This is why I suggested draining the tank. Fuel tanks are not air tight so the ethanol will evaporate and some of the fuel hence the lacquer problems. 

 

Just like the 1977 Ford I've been working on. The fuel tank was lacquered up and all the seals on the carb was shot. Long term fuel contact with hoses, seals, and gaskets will degrade. 

Thank you both for responding.  It's going to take me time to work through this.  I sure hope it's not wiring with rodents.  Squirrels do like the place... anyway my second gen has been parked also but only from about 2018.  

Place moth balls under the dog house, the smell is enough to keep rodents away.

 

No @Dripley,  it not tiny little things your thinking of.

For longer storage don't use any ethanol gas and add seafoam not stabil

I had rabbits and mice eating the wire in the engine compartment of a Volvo stored here for my granddaughter.   I did two things: first i sprayed the engine compartment with a light mist of Critter Ridder, next I propped the hood open just 3½"  with a piece of 2X4 on it's side.  No more problems.   The Critter Ridder smells like cloves.

 

https://www.homedepot.com/p/Havahart-Critter-Ridder-II-32-oz-Ready-to-Use-Animal-Repellent-3145-2/206051392?source=shoppingads&locale=en-US&mtc=Shopping-B-F_D28O-G-D28O-28_1_CHEMICALS-NA-NA-NA-SMART-NA-NA-SMART_SHP&cm_mmc=Shopping-B-F_D28O-G-D28O-28_1_CHEMICALS-NA-NA-NA-SMART-NA-NA-SMART_SHP-71700000059845719-58700005436056249-92700049554889054&gclid=CjwKCAjwlYCHBhAQEiwA4K21mx13bq8emmHeVXhQuiIyb_mjog2rCOhXzDXftsrymSvS1PjyHM9lEhoCkkUQAvD_BwE&gclsrc=aw.ds 

@LorenS, Thanks for the response. Things must be getting pretty bad with them Critters running our country, as I cannot hardly get a rise out of anyone anymore for some reason  

3 hours ago, JAG1 said:

@LorenS, Thanks for the response. Things must be getting pretty bad with them Critters running our country, as I cannot hardly get a rise out of anyone anymore for some reason  

Some are just slower than others.

This chicken was running so fast he passed several cars in a 65 MPH interstate. Passing in the emergency lane and estimated to be doing 95, one of the cars saw him get off at the next exit and tried to follow. He was lucky enough to see which farm he went into, so he pulled up and asked the farmer working outside how this chicken could be so darn fast. The farmer went on to say that some he raises have three legs. He asks why raise chickens with 3 legs and the farmer says well me and my wife and son like drumsticks and that's three of us. Well, do they taste good, he asks? The farmer says, 'I don't know I never caught one"