1999 XLT 4.0 v6 SOHC need help trouble shooting

[Zach1999]

Hi I own a 1999 Ford explorer v6 sohc 4.0 287024 miles. Does not want to hold above 2000 rpms and when you push the gas pedal down towards the floor the engine will not take gas and will not acclerate. Getting codes including o2 sensor and MAF sensor, cut my cats off one was bad got some power back but top speed is still 55mph at best. All this started after I changed the fuel filter, since then have changed it twice, removed cat converters and changed fuel pump thinking spark plugs and wires next any help is greatly appreicated. So main problem is loss of accleration power and top speed. Very new to cars so I apologise if I am being vauge

 

[fastpakr]

What have you done to diagnose the problem to date, other than swapping and/or removing parts?

 

[Zach1999]

Tried to use a PO reader to get codes but I found out I have a OB2D system, other than that I have not ran any "tests" or anything of that nature to diagnose the problem, i know i need to get a "Haynes" manual to start doing specfic diagnostic tests.

 

[fastpakr]

Definitely get some form of OBD2 code reader, whether it's a plug in unit or a bluetooth adapter for your phone. At that mileage, even a compression test may be a reasonable step. Whatever you do, stop replacing parts until you have a better handle on what the issue is.

 

[Zach1999]

That is a really good idea. Probably the conclusion I should've come to, just eager to get this thing running again, I will go tomorrow or Friday to buy a scanner. Thank you for your help so far

 

[Shifferbrains88]

Try disconnecting the MAF sensor and see if it runs normally. A dirty or faulty MAF will do all sorts of nasty stuff. By disconnecting the MAF, the computer will go into a set parameter mode.

 

[Zach1999]

Disconnected it and it seems to run just fine actually better with it being unplugged, actaully it is running almost perfectly no more crazy idle, seems to have more power tobut still wont take too much gas. I hooked it up to an obd2 sensor and it pulled no codes at all this time I do plan on taking it to a shop in 2 weeks to get a diganostic test done

 

[Zach1999]

Can I drive it with the MAF unplugged if it is performing better?

 

[Shifferbrains88]

Looks like you might have a faulty MAF.

 

[Zach1999]

Definetly, it still won't rev above 2000 while driving. But it is at least one problem elimnated

 

[Zach1999]

And it has a bit more power but still very slow accleration

 

[Shifferbrains88]

Have you checked fuel pressure and volume? If so, and in spec I would next check for restricted exhaust.