1992 Jeep Cherokee - Leaking Gasoline?

Check the seal on the gas cap. Most fumes from the vehicle are captured, and burnt while the car is running. When you shut off the car, some of these fumes may leak to atmosphere as the engine's vacuum diminishes, and some of the systems now vent to atmosphere.

Have you done a compression check on it? 10% lower compression could give 10% lower gas mileage.

If you think the engine is in proper running condition, check for air flow into and out of the engine. That would be any restrictions in the air filter system, like a hose collapsing, or a dirty air filter. On the exhaust side the catalytic converter or the muffler can clog, or any of the pipe can warp and become restrictive. Older GM C bodies had double wall exhaust pipes that would de-laminate and block flow as the pipe went over the axle. Looked perfect on the outside, could not pass a marble through it on the inside. Good luck.

Thanks ,You confirm a couple of my ideas and gave me some food for thought Scott

I've got a '92 Laredo with well over twice the miles as yours, just shy of 300k. Mine averages about 20-22 on the freeway and 15-18 in the city.

I gone through a couple of times chasing fuel smells. Once it was an injector seal. I could smell fuel towards the front and it was stronger when I popped the hood. Searched and searched, scratched my head, worried about blowin up... finally figured it out. I had the fuel line weeping a bit once back by the filter just in front of your fuel tank. If you haven't changed that in-line filter yet yourself ...do it. Slide under just in front of the drivers side rear wheel and look up...you'll see it.

125k ... change every vac line and soft fuel hose you can get to.
There's a vac operated plastic water valve for the heater, under the hood on the front bulkhead - passenger side, that likes to snap in half at the worst possible time. Unless you look at it and it's obviously brand new change it. I've gone through 3 of them.

Like Bob C said... do a compression check. I've never had to do rings but I have done the valves a couple of times.

Check the integrity of the distributor; they wear out and then they runout an can cause what you've described.

You probably should talk to a mechanic that has extenisve experience in the fuel system for this vehicle. With that in mind, discuss the use of plastic lines internal to the fuel control system, specifically lines that are hidden inside of the top end. It is a common occurance that plastic lines develop microscopic cracks that allow small quantities of fuel to leak into the intake mainfold and thus pass directly into the combustion chambers. This lost fuel represents a reduction in fuel efficiency. There are occurances where such plastic lines suffer total failure and the engine is totally flooded with fuel, especially on the mid 90's GM V6 engines. The fuel smell is the key that says, low flow fuel leak. Unless you talk with an experienced mechanic on your specific engine, someone that has seen "it all", the chances of you finding it are very low. Until the line fails totally, then it will shutdown the engine, mileage then will be 2 or 3 miles per gallon, if it will run at all.

Do all checks as advised but if your fuel tank is steel it might be leaking at the top of the tank were you cant see. This is where all the road salt ends up and eats the tank over time. Fill her up to the spout and let it sit overnight then get under and look for wet spots at the upper portion of the tank and the tanks seam. Also look at the rubber seal were the fill pipe enters the tank and the area were the metal bands hold the tank in place .

Start it up and get under again to inspect the fuel lines , she has a few years on her and as Neil Young says , rust never sleeps.

Let us know how it goes.