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04 Expedition Hard start and loss of power when driving

My 04 Expedition has recently been hard to start and when driving I get a loss of power for about two seconds. RPMs go down to almost nothing, then the engine kicks in again and it goes up to 3,000. The battery light turns on for a few seconds then off.

i have no codes. I have a new battery and I have tested the alternator, but I haven’t been able to test it when the car loses power.

i have changed the fuel pump, fuel filter, spark plugs, air filter, and boots. I have cleaned the throttle body.

Any ideas as to what this could be? I’ve done a visual inspection of the fuse box by disassembling and then reassembling. I’ve inspected my battery cables but they see fine. Could this be the ECM? Perhaps a sensor is going?

what happens when it is hard to start? engine wont crank at all? or engine cranks, but won’t fire up?

I’d start by double checking battery cables- making sure they are clean and tight. Check them both at the battery, and where they connect to the car at the other end of the cables.

Find the ECM, and check that those connections are tight.

Does the issue happen in any kind of predictable way? Happens after so many miles or minutes running? Only after cold/hot nights? etc, etc, etc.

It is not predictable. It is very random. Sometimes four times in 5 minutes and other times once in 30 min. Day, night hot cold doesn’t change. It cranks but takes a long time to finally start. I’ll double check connections and ecm connections.

when it hesitates to start: if you turn the key on, leave it on for 5-10 seconds, then cycle it off, and then try to start- does that change anything?

Yes. If I run the fuel pump a few times it starts right up. Same as if I turn it on right after turning it off.

In that case, you’ve definitely got a fuel pressure/delivery problem

That’s my thought too, buy what could cause it. Injectors?

It’s possible the battery dash warning light is coming on when this happens just b/c the engine has stalled out, rather than there being something wrong w/the battery or alternator. It thinks the engine is not running with the key in “on”, so it is supposed to turn on. B/c of that warning light tho if I had this problem I’d run some test wires into the passenger compartment and connect it to a volt meter. With the engine off it should read about 12.6 volts, and with the engine running it should read 13.5-16 volts. I’d watch the meter to see what it was saying when this symptom occurred.

You can buy for $10-12 from Amazon a voltmeter that plugs into the cig. lighter socket. I just leave it there all the time. It also reads cabin temperature, handy.

Thanks, that looks like very convenient way for the owner to monitor the battery & alternator voltage. Priced right too.