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99 4’oh


jerkyboyxiii

Well-Known Member
U.S. Military - Veteran
Joined
Jun 10, 2021
Messages
155
City
nebraska
Vehicle Year
2001
Engine
4.0 V6
Transmission
Automatic
My son's ranger: I ran a test pipe in place of the cat pipe. The truck falls on its face and stutters when passing gear hits. Plugs n wires were replaced in feb of 23. I cleaned the throttle body n changed the throttle position sensor. Air filter got changed too. The truck runs super smooth n has no noises or quirks. Any ideas? Gump, you always have a wealth of knowledge…
 
Any codes? Was the TPS the cheapest thing at the parts house or a Motorcraft part? The cheapest ones tend toward wide dead zones on the high and low end of the range...
 
I assume you suspected exhaust blockage, so son had limited RPM at higher speeds?

Clean the MAF sensor, common reason for stumbling with 4.0l OHV Rangers

Now old are the O2 sensors?
O2s are THE ONLY sensors that wear out, 12 years or 100k miles and you need to change them, all 3 in a 1999 4.0l
MPG will also go up if they are older
 
Any codes? Was the TPS the cheapest thing at the parts house or a Motorcraft part? The cheapest ones tend toward wide dead zones on the high and low end of the range...

Pee171 n P174 were present before I ran the test pipe. I cleared those, and they haven't popped back up. I did get a new code that I'm sure was bc the cats are gone (I don't recall the code). My OE TPS was installed when I first noticed the lack of RPMs/falling on its face. I swapped in a cheapo offa amazon just to see if it changed anything. It didnt. Low RPM has always been spot on, regardless of the TPS. Does anybody have the Motorcraft TPS part number handy? I found several different part numbers.
 
I assume you suspected exhaust blockage, so son had limited RPM at higher speeds?

Clean the MAF sensor, common reason for stumbling with 4.0l OHV Rangers

Now old are the O2 sensors?
O2s are THE ONLY sensors that wear out, 12 years or 100k miles and you need to change them, all 3 in a 1999 4.0l
MPG will also go up if they are older

Yup. I suspected an exh blockage so I ran a test pipe. The cat free pipe changed nothing. I will clean the MAF and post back. The 02 sensors were replaced recently by the previous owner. Fuel filter is new too.
 
You can use Vacuum gauge to test for exhaust blockage, and lots of other stuff, one of the better tools in the box and cheap :)

Another good tool is a Bluetooth OBD2 reader, ELM327, under $15 and $5 APP
You can see Live Data while driving, you see what computer sees from any sensor selected
Works on any Vehicle sold in the US/Canada 1996 and up, so not a Ford thing. its the law, still works on 2023's

Live Data can be handy if a problem is not easily ID'ed
Codes are OK, but computer knows less than you about overall condition of the vehicle, lol
 
Hook it up and have a look at TPS, key on engine off
17-19% foot off gas pedal
Press gas pedal down and should see a STEADY rise to 90-92% with pedal to the floor
Any jumps or drops means replace TPS

Next with engine running and warm
select MAF sensor and grams per seconds, g/s
At idle should see around 4, displacement of engine in liters
Slowly raise RPMs and g/s should also go up, no drops or jumps

Next look at Air Temp, IAT or ACT sensor, degrees F
Warm engine go for a drive, should be no big jumps or drops in air temp
 
Last edited:
Ron, this is the elm327 that i would need, correct?

WiFi ELM327 OBD2 Scanner Reader Adapter Compatible with iPhone and Android Phones WiFi OBD 2 ELM 327 Reader Scanner Adapter Diagnostic Tool for Cars and Light Pickup Truck https://www.amazon.com/dp/B0BRKJ38ZQ?tag=959media-20

IMG_8791.png
 
Wifi and Bluetooth are short range wireless signals, so these are like connector "cables" with different plugs at the ends, nothing to do with OBD2 itself, just has to do with connecting OBD2 to your device to use as a screen

I have never used WiFi version, just Bluetooth
If you use Apple phones or tablets then Wifi might be better as Apple does NOT always "play well" with Bluetooth

Android devices will work fine with either

So yes that should work fine with either type of screen
 
Thanx, Ron. I know the USB connects to a laptop. I don't need a computer screen to do what I need. On my VGate for the wife's colly, I connect to my eyephone via wifi. I use the dash command app that I bought. I think I should be able to use the purchased app on countless vehicles. Thanx for the info and for the feedback!
 
I was comparing wifi and bluetooth as two different cable "ends"
But they are not physical cables

Wifi works with Apple or Android
Bluetooth works with Android and sometimes Apple

Apple is the "monkey in the wrench" a POS with attitude, lol, the sooner they go bust the better
 
If you already have the WIFI adapter for the Colorado, you should be able to use it on the Ranger too. No need to buy anything.
 
Senor, i thought of that too. Theyre inexpensive enough to have two:) The other one lives in my wifes truck, n id rather not disturb it…
 

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