Driveability issues... (engine performance)

[Todd82TA]

Hey guys, I have a 2002 Ford Explorer Sport with the 4-liter SOHC V6 (FYI, the 2-door one from 2001-2003).

Anyway, I was hoping I could beg some advice from you guys.

My Explorer has about 76k miles on it. I keep it in pretty decent repair, oil changes on time, etc; however, it's started having somewhat of a driveability issue.

When driving down the road at consistent speeds, or even when accelerating calmly, the vehicle feels like it loses power a little bit. It's not huge, but it kind of feels like when you're driving down the highway and a big gust of wind blows on your car and slows it down for a quick second... or at least gives it some resistance to the acceleration. It's kind of intermittent, and only happens more regularly when it's hot and muggy outside (humid, ~85+, etc).

I checked under the hood and see that it has both a MAP sensor and a MAF (didn't know they came that way?). Could it be a failing mass air-flow sensor?

The car's in pretty good tune... and fortunately (unfortunately? $$$) it has a new transmission as of 20k miles ago.... fluid is still bright red and very clean.

The check engine light is not on, so I ASSUME there are no OBD2 codes... though I can plug it in to check if I need to.


Thanks guys! Any help would be appreciated.

 

[Dweeberman]

Intersting topic as I just ran into this issue myself over the weekend, though the outside temp was 106-109degrees. Felt almost as if the AC compressor would turn on and take power away (didnt have ac on at that time). For me though i was going up in elevation (going camping) so i am sure the elevation and temp combined had an effect. I wish i knew the answer for you, but I am sitting in the same boat you are now.

 

[2000StreetRod]

weak fuel pump?

The fuel in the tank cools the fuel pump. During hot weather extremes the cooling is reduced and a weak fuel pump may result in reduced fuel pressure to the injectors. Have you tested your fuel pressure recently? It should be around 65 psi. Has it been more than 50K miles since you replaced the fuel filter?

You might try cleaning your MAF sensor with MAF sensor cleaner.

I'm really curious about your vehicle having a MAP sensor and a MAF sensor. What is the MAP sensor connected to? Where is it located? Could you post a photo of it?

 

[Todd82TA]

Thanks guys, I appreciate it!

2000SR, I changed the fuel filter around ~45-50k miles (about two years ago).

The fuel pump is original (2002) and I have not checked the fuel pressure.

The MAP sensor, or at least it looks like one, is located on the drivers side of the engine, right behind the power steering pump.

In this picture (see below), if you look DIRECTLY to the right of the EGR valve / vacuum diaphragm, basically right next to the oil dip stick. It LOOKS like a MAP sensor since it has a vacuum line on it, and a single plug. I suppose it could be something else, but who knows. If it is a MAP, I've never seen a car with both a MAP and a MAF... unless it's redundant, or just some kind of random vacuum pressure sensor?

 

[2000StreetRod]

dpfe

That's the differential pressure feedback EGR sensor.