1999 Ford Expedition with Occasional, but Invariably Inopportune Power Loss

Probably not a good way to start out a classified ad, but accurate, nonetheless.

I’ve got a '99 Ford Expedition, which has to last two more years. The problems are multitude, but the one that bugs me the most is an occasional and momentary loss of power when I try to take off from a stop. I push the accelerator, the car starts moving, usually just far enough to get me out into the middle of the road, and then it cuts out for about one second, the whole car shifts forward, and then it comes right back to life. It’s never actually stalled, but the revs drop to next-to-nothing. It seems to happen more often when I’m pulling off of an off-ramp after driving on the highway for a while.

My guess is the fuel pump, but I won’t have the cash to get it into the shop for a few weeks. Also, especially when it’s cold, there’s a mechanical whine, which is rather annoying. It’s a mechanical sound, almost like a dynamo, not belts squeaking, and anyway I’ve checked and dressed them, so I was thinking either fuel pump, power steering pump, or alternator. I haven’t noticed any problems with the battery charge, and it always starts just fine (excepting one morning when it was -20℉, but you can’t be mad about that), and the power steering makes its own special noise, separate from the constant whine, so I was wondering if my legitimate problem and source of minor annoyance were connected.

The thing is really just a piece of crap at this point. It’s got 170k miles on the chassis, but only about 65k on the new motor (previous owner decided it would be a good idea to drive 700 miles at 85 mph, while towing a trailer that was probably too heavy to begin with, and with overdrive on). The electronics system is inhabited by a gremlin whose only purpose in life is to irritate me, the air suspension decides when it wants to level out and when it doesn’t, the door locks were electric, but now 3/5 are manual, etc., etc., etc. /vent

Thoughts? Thanks in advance.

The mechanical whine sounds like it is the typical crappy Ford-all-models power steering pump. You’ll find that thing on Sables, Probes, Tauruses, Escorts, all the way on up to big diesel pickup trucks with a 7.3 V8 like mine… it’s the one with the white plastic reservoir bolted right to the backside, and has no readily-accessible drain procedure to swap the fluid and as a result makes power steering/tranny fluid look like mud. It’s a giant hunk of crap. Mine is doing the same thing and I just recently dropped down some cash for an aftermarket kit to convert my 7.3 to a GM saginaw pump that will probably outlast the engine. Yes, you’ll get a separate groangroan* from the power steering pump when you apply a load to it by turning the wheel side to side, and this will be more pronounced when it’s cold outside and the vehicle isn’t warm. If sucking the fluid from the reservoir a few times and topping off with new fluid doesn’t do the trick, it’s time for a new pump.

Towing an overloaded trailer won’t really harm the engine aside from running higher temps and potentially overheat it… but it WILL readily cook the crap out of a good transmission without warning until it’s too late.

The door locks are probably due to bad actuators, which can add up when the parts are only available at a stealership.

The lurching/stalling condition might be a severely coked intake. Have you taken the intake off and cleaned up the throttle plate and housing? How about the ignition system, done any work to it lately or is it still running the same components that were on the old engine?

I knew I came to the right place. Thank you.

I think that the his decision to tow that trailer in the way that he did was more of a symptom of a larger issue with his approach to maintenance. I don’t think he was very keen on changing the oil, or even checking its level, he was about a quart low when I bought the car, so I think that running the engine at such a high speed for so long with low/crappy oil was what caused the problems.

That’s good to know about the PS pump; I haven’t tried changing the fluid, just checked the levels. I’ll give that a shot.

I haven’t cleaned the intake, but I will now. Any suggestions on a good how-to guide?

I also haven’t checked the ignition system. The engine that’s in it now was brand new a five years ago, it wasn’t a rebuild, so would the ignition system have been swapped then? If not, then it’s the same one that’s been there for 12 years.

Thanks for the quick reply.

Before your next drive, pull the vacuum line from the EGR valve, plug the line & cap the valve. See if that eliminates that momentary lapse of power. This is exactly what my escort was doing when the spring in my original valve got weak. The solenoid was delivering X amount of vacuum, but the valve was opening too much. If that helps then you likely need to replace the valve, though it might pay to have someone knowledgeable check out the whole EGR system.