Wont start, rough idle when starts
#1
08-02-2021
Wont start, rough idle when starts
2000 Ford ranger 3.0 v6 2wd
Sometimes won’t start at all sometimes it will start and shoot up to 5rpm and die. When it does choose to start it idles rough sometimes and overheats randomly when accelerating but the temp gauge instantly falls to normally when slowing down. I have 2 o2 sensor codes but the others are random codes I can’t track down.It says to lean and misfire on 3rd and 6th cylinder I checked spark plugs and wires both good checked battery and tested alternator can’t seem to figure it out. it has been better since I replaced MAF sensor but still not perfect (also randomly leaks coolant an can’t find it)
Sometimes won’t start at all sometimes it will start and shoot up to 5rpm and die. When it does choose to start it idles rough sometimes and overheats randomly when accelerating but the temp gauge instantly falls to normally when slowing down. I have 2 o2 sensor codes but the others are random codes I can’t track down.It says to lean and misfire on 3rd and 6th cylinder I checked spark plugs and wires both good checked battery and tested alternator can’t seem to figure it out. it has been better since I replaced MAF sensor but still not perfect (also randomly leaks coolant an can’t find it)
#2
08-02-2021
Welcome to the forum
Reads like you have a few problems
Need the EXACT Codes, here is a partial list: https://www.therangerstation.com/tec...II_codes.shtml
As you can see on the list, EVERY sensor, or Control, has MANY codes, each means something slightly different
"I think it was.............." doesn't help, lol
Could be your fuel pump is starting to fail, that causes slow or no starts and rough idle just after start up and Lean condition from low fuel pressure
Change fuel filter first if you haven't already, should be changed every 5-7 years
You can rent a Cooling System Pressure tester, many auto parts store loan them for free
Its a radiator cap with a hand pump and pressure gauge
COLD ENGINE
You install the cap and pump up your cooling system to 20psi, it normally runs at 16psi when fully warmed up
Then wait and watch, if there is a leak pressure will start to drop, and BECAUSE engine is cold the coolant will drip down to the ground so you can find the leak
Reads like you have a few problems
Need the EXACT Codes, here is a partial list: https://www.therangerstation.com/tec...II_codes.shtml
As you can see on the list, EVERY sensor, or Control, has MANY codes, each means something slightly different
"I think it was.............." doesn't help, lol
Could be your fuel pump is starting to fail, that causes slow or no starts and rough idle just after start up and Lean condition from low fuel pressure
Change fuel filter first if you haven't already, should be changed every 5-7 years
You can rent a Cooling System Pressure tester, many auto parts store loan them for free
Its a radiator cap with a hand pump and pressure gauge
COLD ENGINE
You install the cap and pump up your cooling system to 20psi, it normally runs at 16psi when fully warmed up
Then wait and watch, if there is a leak pressure will start to drop, and BECAUSE engine is cold the coolant will drip down to the ground so you can find the leak
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Dakota_ (08-03-2021)
#3
08-03-2021
#4
08-03-2021
A "V" engine(V6, V8) has Bank 1(passenger side), and Bank 2(drivers side), 4cyl engine just has Bank 1
O2 sensors are Upstream(sensor 1), or Downstream(sensor 2), downstream O2 is located in or just behind the last Cat Convert, it checks to make sure exhaust is clean enough
A "V" engine will have TWO upstream O2, so TWO sensor 1's
Most vehicles just have 1 exhaust pipe, so just one O2 Sensor 2
Dual exhaust would have two O2 sensor 2s
O2 sensors have 2 parts inside, a heater, and a sensor
4 wires total, 2 for heater and 2 for sensor
To get BOTH of these codes
P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
The Downstream(sensor 2) wiring is either unplugged or has touched the exhaust and melted
Generally it won't be a problem with the O2 sensor, just with the wiring
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
These are upstream O2 sensor codes
Getting both at the same time means the O2 sensors are working OK
You either have a vacuum leak or clogged exhaust..........OR low fuel pressure
P0303 Cylinder 3 Misfire Detected
P0306 Cylinder 6 Misfire Detected
O2 sensors can ONLY detect Oxygen, that's what the "O" is for, too much Oxygen in exhaust is "Lean", too little is "Rich"
Engine is never running Lean or Rich, these terms are to describe exhaust Oxygen levels and fuel trims
When a cylinder mis-fires that means NONE of the Oxygen was used/burned up during ignition
So that oxygen is dumped into Exhaust manifold
O2s detect Oxygen, so....................................lean can be because of the mis-fires, 3 is on passenger side, 6 is on drivers side, so both sides would be effected
Because BOTH rear cylinders are effected it could be a vacuum leak at the rear of upper intake, PCV, power booster, vacuum line, ect.............
But finding the reason 3 and 6 are mis-firing should be the primary goal
Sensors rarely fail, all my 1994 Ranger sensors are still working fine, that's not rare that's NORMAL
O2s do wear out, only sensors that do, but there is no Code, just poor MPG as they run out of chemicals, and eventually you would get a P0133 02 Sensor Circuit Slow Response (Bank 1 Sensor 1)
But nothing wrong with replacing O2 sensors to get best MPG
But stop there, no new sensors, new sensors do not fix problems, common DIY mistake, sensor codes TELL you were to look for the problem, so DON'T SHOOT THE MESSENGER, lol
O2 sensors are Upstream(sensor 1), or Downstream(sensor 2), downstream O2 is located in or just behind the last Cat Convert, it checks to make sure exhaust is clean enough
A "V" engine will have TWO upstream O2, so TWO sensor 1's
Most vehicles just have 1 exhaust pipe, so just one O2 Sensor 2
Dual exhaust would have two O2 sensor 2s
O2 sensors have 2 parts inside, a heater, and a sensor
4 wires total, 2 for heater and 2 for sensor
To get BOTH of these codes
P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P0141 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
The Downstream(sensor 2) wiring is either unplugged or has touched the exhaust and melted
Generally it won't be a problem with the O2 sensor, just with the wiring
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
These are upstream O2 sensor codes
Getting both at the same time means the O2 sensors are working OK
You either have a vacuum leak or clogged exhaust..........OR low fuel pressure
P0303 Cylinder 3 Misfire Detected
P0306 Cylinder 6 Misfire Detected
O2 sensors can ONLY detect Oxygen, that's what the "O" is for, too much Oxygen in exhaust is "Lean", too little is "Rich"
Engine is never running Lean or Rich, these terms are to describe exhaust Oxygen levels and fuel trims
When a cylinder mis-fires that means NONE of the Oxygen was used/burned up during ignition
So that oxygen is dumped into Exhaust manifold
O2s detect Oxygen, so....................................lean can be because of the mis-fires, 3 is on passenger side, 6 is on drivers side, so both sides would be effected
Because BOTH rear cylinders are effected it could be a vacuum leak at the rear of upper intake, PCV, power booster, vacuum line, ect.............
But finding the reason 3 and 6 are mis-firing should be the primary goal
Sensors rarely fail, all my 1994 Ranger sensors are still working fine, that's not rare that's NORMAL
O2s do wear out, only sensors that do, but there is no Code, just poor MPG as they run out of chemicals, and eventually you would get a P0133 02 Sensor Circuit Slow Response (Bank 1 Sensor 1)
But nothing wrong with replacing O2 sensors to get best MPG
But stop there, no new sensors, new sensors do not fix problems, common DIY mistake, sensor codes TELL you were to look for the problem, so DON'T SHOOT THE MESSENGER, lol
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