Weird acceleration issues

[markedman450]

So explorer has been running really good since a fuel pump replacement was done. Now im starting to get a rough idle, doesnt feel like a miss like bad plugs, just idles rough. No vacuum leaks and all new plugs, etc. Also when im on the highway and go to give it gas, the engine will start to get power then all of a sudden rpms drop to 2k rpms and i have to let off the gas and hit the pedal again for it to get away from the 2k range. Its hard to explain but i try to give it gas, it drops the engine to 2k rpms, and unless i floor it it will just hesitate at the range unless i let off the gas and hit it again. Any Ideas.

 

[Tbars4]

...after changing the fuel pump, have you replaced the fuel filter???

 

[markedman450]

Yep, fuel filter, plugs, wires, etc. Cleaned the IAC. Ill be on the highway and i go to accelerate and it starts to then just drops to 2k like its missing power. I either have to floor it or let off the gas and press it again then it goes up to power.

 

[Tbars4]

...have you pressure tested the fuel pressure reguator, fpr??? i'm not all familiar with your year but there are writeups for this...but that would be my guess and here is a bump for your thread...

 

[markedman450]

Just had a brand new pump and regulator put on cause of a pressure issue. And it did this before and after that was installed. It just feels like the throttle cable is not connected right almost. I know it is but thats what it feels like. Ill have the pedal slightly down and as i push farther it just hangs at 2k rpms until i almost floor it or let of the pedal and press it again, then it comes to life. Any chance on the TPS maybe?

 

[Lt.Jim]

I had the same issue with my 94. Replaced the fuel pump and fpr. Started running real crappy. Could not get a code. Until yesterday. I got a high and low voltage from the maf. When the rough idle starts try unplugging the maf and see if the idle changes. Mine idled smooth with the maf unplugged. Plugged it back in and the idle went to hell.

Guess what i'm relacing tommorow. I tried cleaning it with no success.

 

[trevell407]

I have EXACTLY the same problem,
I think it is happening to mine because of a leak in the seal between the upper and middle part of the intake,
Im going to replace them soon and i'll let you know if it helps,
if you figure it out let us know

 

[markedman450]

That would explain the idle but would that also explain the acceleration issues.

 

[Lt.Jim]

I swapped out the old maf with a new one and that seems to have done the trick. I would suggest you try cleaning yours first(you may get lucky) before shelling out $100+ for a new/reman one.

 

[Bills98Explorer]

If my mind remembers correctly there was a TSB on this issue that covered a sticky throttle.I know longer work at a Ford dealer so I'm not able to double check this.If anyone has access to Ford TSB could they look into this please?

 

[trevell407]

that would be quite helpful if someone could check it out, its driving me crazy

 

[markedman450]

Yea i would love to know because its annoying having to let of the gas and hit the pedal again just to accelerate.

 

[5.0ExplorerMan]

I definetly recommend checking the MAF sensor. It likely could be dirty or bad. If it has been happening for a while, your air/fuel ratio could be all out of whack. I had a similar problem starting, but fixed it before it got worse just by cleaning the MAF. The problem came to light when my Explorer backfired 2-3 times in a matter of a month. My fuel mileage had been getting worse with each passing tank. I thought it might be because of all the engine upgrades I had done. I had just put a bottle of fuel injector cleaner in the tank and thought maybe the fuel was too rich/lean. I cleaned the MAF and it solved the backfiring, the bad fuel milage, and the minimal HP I was getting. You may have to drive around for a few days before the air/fuel ratios correct themselves, but I noticed massive improvements in just 3-4 days and my Explorer felt better with each passing day. I am still in the market for a new 75mm MAF when funds become available. The MAF cleaner costs maybe $6-7 at most part stores and is an easy, cost-effective way to solve this problem.

 

[Charlie]

Did you try unplugging the MAF at idle to see how it runs?

 

[trevell407]

My maf sensor is only 2 or 3 months old,
I just did new motor craft plugs and wires yesterday and that helped a little but there definatley is still a hesitation when its in o/d and I hit the gas it just hangs out at 2g's unless I floor it or take my foot completely off the pedal and hit it again.

 

[markedman450]

Thats the exact same thing im having. It just seems to hang there like its bogging down. MAF i would think would cause rough idle but i dont see it causing the problem were having. I thought it might be a leak by the TB but i found nothing. Im really lost on this one.

 

[trevell407]

I found a vaccum leak somewhere in the seal between the upper and middle part of the intake, im having them all replaced monday or tuesday,
I think its lost power in all ranges but it is just a lot more noticable when its in o/d,
I'll let you know if it solves our mistery.

 

[markedman450]

Im wondering if i have a leak by my throttle body.. I hate driving it right now cause i feel like i have to keep pumpin the gas to get it to kick out from 2k rpms

 

[mittelmeier]

If you have a leak in your throttle body it must be after the trottle body because I had one at the maf and other than the throttle plate freezing open my x never ran better. A little silicone around the sensor and no more freezing. I'd try unplugging the maf when it acts up and if that doesn't fix it then unplug the tps. It should be one or the other.

 

[markedman450]

So it might be the TPS? Thats alot cheaper of a part so i wouldnt mind that haha. Is it ok to unplug it and drive it? ALso is there any chance its something with the tranny? Like a sensor that decides when to shift in and out of gear?