Power surge?

[Nick Nielsen]

1999 Ford Expedition XLT...
283,*** miles...
Tune up consisting of all new 100,000 mile plugs, and replaced 3-4 coils....
Cold air intake gasket replace don't as well...
From time to time, one cylinder drops (I got coolant and water everywhere when I did a heater core flush in hopes of getting heat, still, to no avail do I have heat) blew out the coil and spark plug housing with compressed air to get the water out and it runs fine now, but from time to time, My number 8 cylinder goes out (assume its #8)
I don't know if it correlates with my next problem, it's happening more frequent, every time I take off from a stoplight, I'll be gradually accelerating and then the whole truck shuts off/surges, doesn't affect lights or stereo, but it last for a second or so and then the truck starts running again and keeps going like nothing happened. Is this common? I've looked it up and found nothing. Thanks for the feedback!

 

[stamp11127]

No it isn't a common problem. What do the gauges & radio do when it cuts out?

 

[Nick Nielsen]

No it isn't a common problem. What do the gauges & radio do when it cuts out?

Nothing, everything stays running, lights don't dim, brake pressure stays strong and same with steering. But for some reason, it's like every single cylinder skipped a beat and they all misfired or didn't fire at all and then they come back. Something to do with the computer?

 

[stamp11127]

At this point you don't know the cause since it is intermittent. Next time it occurs note the rpms then give it more throttle quickly and see if it responds as fast. You don't need to floor it. Be prepared for the acceleration if it still hesitates. You are looking for "the facts" of when it occurs - looking to see if it is throttle related.

It could be "something with the computer" more along the lines of poor connections.

 

[Nick Nielsen]

At this point you don't know the cause since it is intermittent. Next time it occurs note the rpms then give it more throttle quickly and see if it responds as fast. You don't need to floor it. Be prepared for the acceleration if it still hesitates. You are looking for "the facts" of when it occurs - looking to see if it is throttle related.

It could be "something with the computer" more along the lines of poor connections.

Will do, I've tried picking up on the Rpms after it drops, it surges and then instantly brings it up. What else can I do to get more information?

 

[Nick Nielsen]

Forgot to add, usually it's in the 1k to 1300 rpm range, slight throttle above idle

 

[stamp11127]

Do you have access to a scanner to verify sensors?

 

[Nick Nielsen]

I do not unfortunately, but what do you mean 'verify sensors'? I can take it to advanced auto or something to get codes read.

 

[stamp11127]

The advanced scanners will graph the signals from sensors and display multiple sensors at the same time. This allows you to compare crank and cam sensors together and verify their operation along with any other sensors you want to test.

Did you use name brand coils for the replacements or the "El cheapo" brands?

 

[98eb5.4]

is the engine light on? not sure what you mean by ~ "replaced 3-4 coils & assume #8 is acting up"?

i'd start another thread for the no heat issue, tons of info out there for that


don't as well?

Cold air intake gasket replace don't as well...

 

[Nick Nielsen]

I didn't mean the 'don't as well' I meant it was replaced as well. And the light is on, haven't reset it yet, last time I checked codes it was saying number 4 and number 8 cylinders are lean/rich (cylinders were out due to water still in housing and it was shorting the coils) and it also reads plugged cats, I ignore that one, I took off the muffler for the nice sound which I'm sure it pulls a code as well, haven't checked recently. It was in the shop when it got its tune up and intake gasket replaced, they checked codes by plugging it into their machine, they never said if they tested sensors. I've come to the conclusion that, with 283,5xxx miles, since 2nd gear engages between 1200-1600 rpm range, I assume it's just the transmission shifting and having some sort of delay. Sound reasonable?

 

[Nick Nielsen]

Also, they were replaced with master raft coils, they were $70 if I remember correctly.

 

[98eb5.4]

i'd get a code reader, one i use is 20 bux, then go from there

 

[docraymund]

Try checking engine compression on all cylinders. They should be almost the same.

 

[stamp11127]

Please explain how unbalanced or low compression manifests a problem at a specific rpm range.

 

[toomanytoys]

That's funny. My 98 does the same thing. I wouldn't call it a surge though, more like hitting a rev limiter. Only happens when the truck is fully warmed up and at light throttle between 1300-1500 rpm. I've done plugs , coils, fuel filter and pump all with no change. Next on the list is a tps test. There are no codes stored or pending

 

[Nick Nielsen]

I've done pump, and fuel filter as well. Bought the truck for $600 in Maryland (live in VA), was suppose to be a running and driving truck with 'little heat' and bad fuel pump. Guy screwed me over after it needed a $1200 intake gasket replaced in the shop. Had 2 or 3 bad cylinders that were fixed with coils and plugs. I wouldn't describe mine as a rev limiter because I can push it up as far as I want (I assume) with no problem or hesitation. But the problem seems to happen after it's warm and taking off from a dead stop in the 1300-1500 rpm range. Not related, but I flushed both heater cores, little to decent flow up front and flow in back and literally no heat. Actuator works, thermostat replaced, water pump replaced, and full coolant system flush and no heat. I started out with little heat and I'm literally down to none, I expected something more than what I started with but went backwards...

 

[toomanytoys]

I can rev mine past it as well. It's just that one particular spot in the rev range. As far as the heat goes you need to check the blend door and make sure the solenoids and doors are opening when you command heat

 

[stamp11127]

For the no heat issue:
Disconnect the outlet hose from the front heater core. Using a long piece of heater hose, run the hose from the outlet back to the surge tank fill hole. Warm up the engine and see how much flow you have coming out of the core.

Unless the block is squeaky clean after a flush, all the little rust particles continue to flake off and clog the core.

With your mileage you may want to pull the front cover and check the timing chains & guides. The plastic used on the guides has a little history on failing and potentially seizing the engine by blocking the oil pickup.

 

[Nick Nielsen]

Blend door for sure works, put a hole behind glove box to make sure it was moving, and solenoids? What solenoids? And for stamp11127, I've flushed it 3 times now, rust stopped coming out but still little flow. Really don't want to put 16+ hours into tearing the dash apart and putting it back together. And thank you for that, I didn't know that, during summer break (still in school) I'll see if I can do that.