Intermittent misfire 2.9
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Joined: Mar 2024
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From: Marina del Rey
Intermittent misfire 2.9
Hello all!
Hoping to get some assistance on the old 2.9.
The long version is: I was driving my truck, and it suddenly cut off. Ended up not having spark.
Replaced distributor, TFI, and coil and it ran again. Timing was tough to set but finally got it to idle.
It ran horribly when it hit 3k rpm and would cut out like crazy.
after a lot of diagnosis, I found that one of the O2 sensors was bad and the fuel pressure regulator was leaking.
After replacing those, the ranger still ran awful.
Removed plugs and found 2 of them had cracked.
After replacing all 6 plugs the truck ALMOST runs like it did before the engine shut off and lost spark.
I am currently getting an intermittent misfire, primarily at idle and low load. The ranger revs well, has good power through the rev range and seems generally healthy. However, every 30 seconds to 1 minute it will ALMOST cut out. Rpm will suddenly drop to ~500 but only for a very very short time. Like a single cylinder misfire or the key is being turned off and back on once rapidly.
This is also replicated when cruising. The truck will shutter or stutter once and then run fine.
Hoping to get some assistance on the old 2.9.
The long version is: I was driving my truck, and it suddenly cut off. Ended up not having spark.
Replaced distributor, TFI, and coil and it ran again. Timing was tough to set but finally got it to idle.
It ran horribly when it hit 3k rpm and would cut out like crazy.
after a lot of diagnosis, I found that one of the O2 sensors was bad and the fuel pressure regulator was leaking.
After replacing those, the ranger still ran awful.
Removed plugs and found 2 of them had cracked.
After replacing all 6 plugs the truck ALMOST runs like it did before the engine shut off and lost spark.
I am currently getting an intermittent misfire, primarily at idle and low load. The ranger revs well, has good power through the rev range and seems generally healthy. However, every 30 seconds to 1 minute it will ALMOST cut out. Rpm will suddenly drop to ~500 but only for a very very short time. Like a single cylinder misfire or the key is being turned off and back on once rapidly.
This is also replicated when cruising. The truck will shutter or stutter once and then run fine.
Thread Starter
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Member
Joined: Mar 2024
Posts: 4
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From: Marina del Rey
Today's update: checked compression. Maybe should have started there...
Preface: Cylinder 6 is misfiring
Compression reads 130 across cyl 1-5 and cylinder 6 is 110.
Signs of failed injector in cylinder 6. So going to try and replace it. Will post update once injector is replaced.
Preface: Cylinder 6 is misfiring
Compression reads 130 across cyl 1-5 and cylinder 6 is 110.
Signs of failed injector in cylinder 6. So going to try and replace it. Will post update once injector is replaced.
Thread Starter
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Member
Joined: Mar 2024
Posts: 4
Likes: 1
From: Marina del Rey
Was trying everything I could before suspecting motor. The engine has about 30k miles and was a rebuild by S&J engines.
Unfortunately, the last step is valves. So... That's what we'll do. Luckily s&j has a 100k mile warranty but they only cover parts at $50/ hour...
Unfortunately, the last step is valves. So... That's what we'll do. Luckily s&j has a 100k mile warranty but they only cover parts at $50/ hour...
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