1997 Ranger XLT 4x4 4.0 OHV (VIN:X) Mileage:254,000

I had the head gaskets, fuel injectors, alternator, battery ,and coil pack and fuel filter replaced back in November 2018.

Starting about April (2019), it has become hard to start in the mornings. I have to let it turn over a few times...stop...and try again. It immediately starts the second try.
After reaching warmup temps, it would start to "miss" or "stutter" until I drove her a few miles then it would clear up.
I should have gotten her looked at then but no codes where showing and I honestly thought I had more time to get her looked at before I drove her again.

Yesterday a friend's truck broke down while trying to pull his boat out of the water. He called me and I went down with the ole girl and pulled his truck (boat and all) up the ramp into the parking lot. I noticed it took ALOT of effort to pull them out, more than it should have anyway.
On the way home the check engine light came on. The code pulled was P0420.

Since this code pertains to the cat, used my infrared therm to check it. The intake is around 350 and the outlet is around 150. I am assuming the cat is clogged due to the head gasket leak.
Now the engine is "missing" "stuttering" really bad.

I took both O2 sensor out above the cat to relieve some pressure to see if the "miss" would go away, thinking the clogged cat may be causing back pressure. It did not go away. The best way to describe it is, it sounds like popcorn.
It does seem to be only coming from the Bank 1 side. exhaust.

Keep in mind when listening to the mp3 that the O2 sensors are removed. I do not have an exhaust leak as it may sound like it.


Any ideas on where to start?

 

You can use a vacuum gauge($20) to test many things on a gasoline engine

Including partially blocked exhaust

Article here: https://www.gregsengine.com/using-a-vacuum-gauge.html

"Popping" noise can be rich running and Cat getting hotter, would also set the P0420 code

Cat(and O2 sensors) need 600degF and up to work so can only be tested after warm up
OUT pipe should be about 75deg lower than IN pipe

 

Sounds like after-fire... unburnt fuel igniting inside the manifold.

 

Before I spent the money on a vacuum gauge, I decided to test the MAF sensor.
I used these instructions on how to do so:
https://easyautodiagnostics.com/ford...sensor-tests-3

The results were, the multimeter did not read anything. I followed these instructions to the letter.

 

MAF sensor won't cause the symptoms

But pull off the MAF's 4 wire connector and test Red and Black wires for 12volts with key on, thats the heater voltage, same 12volt wire used by injectors

Plug connector back in to test Tan and Light blue wire, the sensor wires, they use 0-5volt range
Have to start engine to test them
Connect meter to tan and light blue wire, I use sewing pins to pierce wire to test voltages
Should see about 0.5-1 volt, + or - doesn't matter, depends on idle RPMs
As you increase RPMs voltage should go up, 3.5v is about max, 6,000+ RPMs

 

Ok. so I did as you said RonD. The Red and Black wires tested 12v but, got nothing on the Tan and Light Blue wires.
I bought a new MAF sensor and installed it. Erased the codes and took a drive. The check engine light came back on about 10 miles later.

The 2 downstream and the one upstream O2 sensors are less than a year old.

Now it has 3 new codes:

P0155 - O2 Heater Circuit Bank 2 Sensor 1

P1151 FORD - Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 2

P1443 FORD - EVAP Control System Purge Control Solenoid or Purge Control Valve Fault

I bought a vacuum test gauge. I unhooked the tube going from the brake booster to the intake and used this hose for the vacuum test.

The engine was warm as I did this as soon as I got back from the initial drive after the new MAF was installed.
The vacuum gauge stayed in between 20~21 HG which is in the recommended range.
I then bumped the throttle and the gauge went to ZERO and back to 20~21 HG and stayed there for at least 10 mins as I didn't know how long I should leave the gauge hooked up.

 

Did you test the Tan and light blue wires with new sensor installed?


You have 2 upstream O2s, one on each bank(side) of a V6 engine
One downstream, if you have single exhaust, after the Cat Converters

Sensor 1 is an upstream sensor
Sensor 2 is a downstream sensor

Bank 1 is passenger side
Bank 2 is drivers side
(but not in England, lol)

So bank 2 sensor 1(B2S1) is the upstream O2 sensor on drivers side
Both codes are for that sensor, 1151 and 0155

The O2 heaters are powered by fuse #3 in engine fuse box, but all 3 share that fuse, so you should get 3 "heater codes" if fuse goes

Check the connector for this O2 sensor.
O2's make their own voltage, .1v is Lean, .9v is Rich, so if connector is off or loose then "heater code" and "Lean code" for that sensor


P1443 Evaporative Emission System Control Valve (low/no flow)

When you have engine codes you should look at a full list of the codes, as seen here: https://therangerstation.com/tech_li...II_codes.shtml

P1442 Evaporative Emission System Control Leak Detected
P1443 Evaporative Emission System Control Valve (low/no flow)
P1444 Evaporative Emission System Purge Flow Sensor Circuit Low Input
P1445 Purge Flow Sensor Circuit High Input
P1446 Evaporative Vacuum Solenoid Circuit

And these
P0440 Evaporative Emission Control System Malfunction
P0441 Evaporative Emission Control System Incorrect Purge Flow
P0442 Evaporative Emission Control System Leak Detected (small leak)
P0443 Evaporative Emission Control System Purge Control Valve Circuit
P0444 Evaporative Emission Control System Purge Control Valve Circuit
P0445 Evaporative Emission Control System Purge Control Valve Circuit Shorted
P0446 Evaporative Emission Control System Vent Control Circuit Malfunction
P0447 Evaporative Emission Control System Vent Control Circuit Open
P0448 Evaporative Emission Control System Vent Control Circuit Shorted
P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction
P0450 Evaporative Emission Control System Pressure Sensor Malfunction
P0451 Evaporative Emission Control System Pressure Sensor Range/Performance
P0452 Evaporative Emission Control System Pressure Sensor Low Input
P0453 Evaporative Emission Control System Pressure Sensor High Input
P0454 Evaporative Emission Control System Pressure Sensor Intermittent
P0455 Evaporative Emission Control System Leak Detected (gross leak)

Computer has all these to choose from and chose P1443

could be electrical or pressure sensor fault, doesn't effect engine operation, I would wait to see if computer can narrow it do with another code



Vacuum looks good
Vacuum testing is short term tests, no need to wait and watch vacuum
Blimp throttle and it should drop under 2" then pop back up instantly so no blocked exhaust

 

Sorry for wasting your time on the O2 Sensor code RonD.

I did not do the main step after replacing/testing part(s). That is check behind myself.
I just checked the codes and posted them before checking behind myself..

After reading your reply this morning, I went to test the O2 sensor and lo and behold the damn thing had come unplugged.
I MADE SURE IT WAS FULLY PLUGGED IN THIS TIME!

I had to go check on a job this morning, this is about a 3 hour drive round trip. So far no codes have come back.

The "popping" noise seems to have dissipated drastically as well. Hopefully when the computer "catches up", it will correct this as well.

Again, I apologize for not checking behind myself and I do (and I'm sure I'm not the only one) appreciate all you do and have done for the Ranger fans in the forum RonD.

YOU"RE AWESOME!

 

Good work

Thanks for the update

I worked on a friends car for an hour, it died at the side of the road, could not keep it running..................................it was OUT OF GAS
Diagnosis: broken fuel gauge, and idiot mechanic, lol.

Never assume, I have many more stories like that, so do not feel bad, you learned, and you learn better on failures than successes, that SUCKS but its true