99Ranger misfire
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From: sumner, Washington
99Ranger misfire
I recently bought a 99 ranger 4cyl.
I had a misfire in cylinder 4 and had a code for running to rich.
The vehicle would die on me every time i came to stop when running cold. It would not die as frequent when the car was warmed up but still lost power and would almost die when coming to a stop. Decided to change spark plugs and wires and issue got worse. Car will start with no issue but run really rough, and dies after start or when i give it gas. When i release the clutch after starting it i hear a knocking noise. im stuck on what to do and any help would really be appreciated.
I had a misfire in cylinder 4 and had a code for running to rich.
The vehicle would die on me every time i came to stop when running cold. It would not die as frequent when the car was warmed up but still lost power and would almost die when coming to a stop. Decided to change spark plugs and wires and issue got worse. Car will start with no issue but run really rough, and dies after start or when i give it gas. When i release the clutch after starting it i hear a knocking noise. im stuck on what to do and any help would really be appreciated.
Welcome to the forum
1999 2.5l SOHC 4cyl has dual spark plugs so a misfire is usually never spark related, can be but a long shot
Both spark plugs fire at the same time, so both spark plugs, both coil packs and both wires would have to fail to get a spark misfire
The point of dual spark plugs is more power
In any case, if it got worse after changing spark plugs, check the firing order on the coil packs, very easy to mess that up
Diagram here: https://ww2-secure.justanswer.com/up...6_190103_1.gif
You will need to do a compression test
Remove all 4 spark plugs on the passenger side of engine FIRST, then test each cylinder and write it down
Expected is 150+ psi
Lean and rich codes come from misfires, they don't cause misfires
So you need to solve the misfire issue first
What did the old spark plug tips tell you about conditions in each cylinder?
Bright white is coolant leaking in, bad head gasket or cracked head, coolant level should be going down
blackish is oil or too much fuel getting in
Light brown/tan is good cylinder conditions
1999 2.5l SOHC 4cyl has dual spark plugs so a misfire is usually never spark related, can be but a long shot
Both spark plugs fire at the same time, so both spark plugs, both coil packs and both wires would have to fail to get a spark misfire
The point of dual spark plugs is more power
In any case, if it got worse after changing spark plugs, check the firing order on the coil packs, very easy to mess that up
Diagram here: https://ww2-secure.justanswer.com/up...6_190103_1.gif
You will need to do a compression test
Remove all 4 spark plugs on the passenger side of engine FIRST, then test each cylinder and write it down
Expected is 150+ psi
Lean and rich codes come from misfires, they don't cause misfires
So you need to solve the misfire issue first
What did the old spark plug tips tell you about conditions in each cylinder?
Bright white is coolant leaking in, bad head gasket or cracked head, coolant level should be going down
blackish is oil or too much fuel getting in
Light brown/tan is good cylinder conditions
no compression
On a 2.5l SOHC its most likely it needs a new timing belt, it has skipped 1 or 2 teeth
Your average compression is 102
And the lowest is 90 which is only 10% off
Highest 115 which is 15% off
So they are within "normal" parameters, just very low
I would check the timing, for sure, before swapping the engines
Your average compression is 102
And the lowest is 90 which is only 10% off
Highest 115 which is 15% off
So they are within "normal" parameters, just very low
I would check the timing, for sure, before swapping the engines
Last edited by RonD; Jan 18, 2024 at 05:39 PM.
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