I have a 2001 Dodge Dakota 4x4, 3.9L V6. It has ~110,000 miles on it and, up until recently, was running strong. The past few months I’ve seen a drastic drop-off in gas mileage. I used to get 275-300 miles off of 16 gallons; recently that has dropped to 200 or fewer. I’ve had the oil changed or changed it myself every 3,000 to 6,000 miles, and changed the spark plugs less than a year ago. I had a fuel system cleaning done last year, too. It has a newer air filter, and I’ve added fuel injector cleaner a couple times. The tires are at the appropriate pressure, and still have a decent amount of tread.
It’s been idling a little high, sometimes consistently, sometimes intermittently. It often makes a sort of gurgling noise, like the sound of a kitchen sink draining or a diesel engine running. Every once in a while it emits a high pitched squeal/squeak when accelerating.
In a few month’s time, I’ll be driving around 2,700 miles with it, so I really need to get this problem taken care of. For an older vehicle and a pickup, I know I can’t expect stellar gas mileage, but I’d like to get it up to 17-19 mpg or so again. The major issue: I don’t have a mechanic that I trust. I’m used to going to the chain companies, and I always feel like they’re giving me the run-around because I’m pretty clueless when it comes to anything beyond oil, filters, and spark plugs, and I can never tell if they’re being honest with me. I know that gas mileage problems are tricky to begin with, but I really don’t want to take the truck in someplace and rack up hundreds of dollars worth of ‘repairs’ that don’t actually solve the problem.
I plan on getting a locking gas cap in case someone has been siphoning off my fuel, but I haven’t noticed a drastic drop overnight on the gas gauge and, given the age of the engine and the noises it’s making, I don’t doubt something mechanical is going on. I just don’t know where to start. Before I take it in to have it looked at, I’d like to have a better idea about what might be causing the problem. All the better if I can try a few things myself.
Anyone run into this problem before, or have any ideas what might be going on? I’d really appreciate any advice.