I have a 1989 Ford F-150 4x4. What would cause it to use a full tank of gas in 2 days when only driving 104 miles in those 2 days.
I had a full tank of gas on Monday. Drove to work Mon and Tues, got up Wed morning, started truck, it was running rough and smelt like it was flooding and it was blowing black smoke from tail pipe and I only had 1/8 of tank of gas left. I only drove the truck 104 miles in the two days. I know I don't get the greatest gas mileage but this isn't right. I checked and the egr line was unconnected. Reconnected it, put more gas in truck but still is using way way to much fuel. Any ideas what could be wrong? It just started this.
Check your fuel pressure. If the pressure is to high your injectors will be injecting more fuel than required (ECM fires injectors for a certain amount of time vs. engine load, if the fuel pressure is high you get more fuel for the same pulse). Usually caused by the pressure regulator. If the pressure is stable you may have sticky or failed injector(s). Check your oil if there is an excessive gas odor this is the likely cause. Repair the injector(s) and change the oil.
Odd it would do this upon startup and not when you parked it the night before. Hopefully no relationship issues. Check to make sure no contaminates were introduced.
A blown Fuel Pressure Regulator will induce fuel into the intake and cause a massive fuel consumption problem. A stuck-open injector (although rare) can do it too. With the engine off and cold, remove th vacuum line at the Fuel Pressure Regulator and turn the ignition to "run" - not start. If ANY fuel comes out of the vacuum port of the regulator, there's your problem. A MAP sensor can cause this concern too. A low vacuum signal will make the computer think that the engine is under high load and command the system to go full rich.
Looking for a Used F-150 in your area?
CarGurus has 205,090 nationwide F-150 listings starting at $1,779.
Search Ford F-150 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford F-150 Experts