I have a '99 Ranger with about 86K miles. Recently I started having problems with it dieing. A week ago, I ran the fuel pretty low, refilled and drove about 45 miles that day. The next morning, when I went to start it, it would start then die.

Given the miles on the truck and the low fuel level the day before, I decided to just replace the fuel filter. This helped in as much that it would sputter a few seconds longer after starting before dieing again. Again given the age and miles and previous conditions, I decided to replace the filter sock. I also replaced the pump while I had the bed off and the tank open so I wouldn't have to go through that again. This didn't help either.

I haven't checked the fuel pressure with a gauge, but if I press the test connection while the truck is at idle, I can shoot a stream of gas up to the hood.

If I baby the gas pedal a bit, I can run the engine long enough to get it warm and at that point I have a good idle. But if I go to slightly open the throttle, it will die and give a cough through the intake. With the top of the tank open, I pulled the pump assembly up far enough to look at the return line. There is a strong stream of fuel there that goes away when I have someone goose the throttle making me believe that the relief isn't stuck open.

The check engine light is off, my OBD II reader shows no codes pending or stored. Monitoring the throttle position sensor with the OBD II reader indicates that the TPS sensor should be OK. The battery cables and voltage are good.

I don't know what to check next. I suspected bad fuel, but I buy my gas there all the time and none of my other vehicles are having issues.

I'm out of ideas.

 

this happened to me and i also have a 2.5 i brought it to the ford dealer and they replaced my mass air flow sensor and it ran great. it sounds like the same problem i had. the part is $300 but it is easy to replace. this is the only problem i have ever had with my truck. Mine also never had the engine light on.

 

go buy a 5 dollar can of cleaner and clean the MAF before you spend 300 dollars. :D also it could be an ignition system problem. getting a pressure reading at the rail would be helpful in troubleshooting.

 

I left my good multimeter at work this weekend. I'll check my MAF signals when I get it. My OBD tool does show the MAF signal, but it displays it in something like g/sec and I've not found a site that indicates what I should be seeing. I have found some sites that show a voltage indication. I also seen to remember troubleshooting my Probe's MAF by unplugging it and noting the effect it had on the way the engine ran.

I agree with the gauge. I'd never rely on this kind of troubleshooting in my job. If I continue to suspect this is fuel related, I'll pick one up. I have a '99 Expedition that will one day need fuel system diagnosis too I'm sure.

 

i would try the fuel cleaner. i was having trouble starting in the morning, but i put in the cleaner, and its working fine.

 

me and my buddy both have 2.5L's and we both had this same problem and both got our mass air flows sensors replaced and they both worked 100% after that.

 

I'm certain it is the MAF. I went out this morning and started it with the MAF unplugged and she runs strong. Autozone has a reman for about 90 bucks after core exchange. In retrospect, this truck has had a gradual decline in power and fuel economy that I simply didn't notice. Given that, I'll replace it rather than try to clean it.

 

Sounds like my old Dodge van that I ran low on fuel. When I checked the fuel pressure it was within range, but every couple of seconds the needle would fluctuate just a bit - the worn pump was pumping air bubbles with the fuel causing the surging and dying.

 

glad i could help

 

My girlfriend has a 2001 Ranger with the 2.5 and manual transmission. It has 170,000 miles on it, and has had power loss issues since she bought it 4 years ago with 100,000 miles.

Performance-wise, it generally drives well. However, if driven hard (70 mph and above) it will eventually lose power, not recovering for about 30 seconds to a minute. Once it recovers, it's fine until driven hard again.

It also seems to be reluctant to pull above 3500rpm - it wouldn't surprise me if this is typical for the 2.5.

Wires and plugs have been replaced recently, the fuel filter has been changed periodically, and the MAF was cleaned recently. Cleaning the MAF appeared to help around-town driveability but didn't clear up the power loss with hard driving.

The Check Engine light stays off in around-town driving, but comes back at the next restart if it's been driven on the freeway at 70 and above for an extended period. When checked with a scan tool, the codes indicate a lean-fuel condition being experienced.

Her family happens to have two older Ford Explorers, one with the SOHC 4.0 V6, one with the OHV 4.0 V6. They also have a 98 F150 with the 4.2 V6. Would the MAF from one of these be interchangeable? It'd be nice to be able to troubleshoot without buying a new MAF.