Misfire help
#1
Driver School Candidate
Thread Starter
Misfire help
2008 ES350, misfiring when car warms up, getting P0300, P0302, and sometimes P0306, have changed plugs, coils and swapped fuel injectors still misfiring, any ideas
#2
Check the compression on those two cylinders.
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rodster239 (01-28-23)
#4
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#5
Driver School Candidate
Thread Starter
so that’s interesting because the wires had been redone and weren’t seated correctly and a couple pulled out easily… I redid them all and still getting a misfire, my theory is those plug wires shorted the ecu… thoughts?
#6
Moderator
The coil wires can be damaged during replacement. Check them carefully for breaks etc. including Squirrel/rodent damage.
#7
Driver School Candidate
Thread Starter
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#9
Pole Position
Knowing your wiring was redone, I would certainly focus on it. If the engine runs well, but simply throws misfire codes, I doubt any of your wiring is incorrect, so you likely don't need a wiring diagram to fix it. Make sure all your connections are clean, tight, and protected from the elements. If any of your connectors are broken or compromised, replace them, or have them replaced. If you aren't experienced with automotive wiring, you may want to have it done professionally by a shop that specializes in this type of work. However, I don't recommend you take it back to where your recent re-wiring work was done. They likely are responsible for your continued problems, so I wouldn't trust them again. Ideally, they should refund whatever they charged you, if the misfiring codes are due to their poor work.
#10
Moderator
You can join the Toyota Technical Information System for 2 days for $20 and see what you need to check the wiring is correct. Plus anything in the service manual.
https://techinfo.toyota.com/techInfo...tis&_nfpb=true
https://techinfo.toyota.com/techInfo...tis&_nfpb=true
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rodster239 (02-04-23)
#11
Driver School Candidate
Thread Starter
I’m pretty experienced with wiring, I’m an aircraft electrician, bought the car with the misfire so I’m thinking the bad wiring job shorted out the ECU, it does actually misfire so definitely have an issue, but yes wiring is tight now
#12
Pole Position
How's the misfire manifesting, i.e., audible, stuttering, lagging, smoking? Is it worse under some conditions than others? Is it misfiring only when cold, or only after warm up?
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
#13
Driver School Candidate
Thread Starter
thanks for the reply, it seems to misfire only after warming up, if driven for a while it’ll start lagging and stuttering but for the first 15-20 mins you can’t notice anything
How's the misfire manifesting, i.e., audible, stuttering, lagging, smoking? Is it worse under some conditions than others? Is it misfiring only when cold, or only after warm up?
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
#14
Driver School Candidate
Thread Starter
159000 miles, no signs of coolant in oil or moisture, no cooling or heating issues, I’ve inspected all the lines for leaks and can’t seem to find anything, except I noticed something I thought was weird about my air box, will post pics when the sun comes up…
How's the misfire manifesting, i.e., audible, stuttering, lagging, smoking? Is it worse under some conditions than others? Is it misfiring only when cold, or only after warm up?
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
How many miles on your ES? Any signs of head gasket issues, such as cooling system issues like high temps, low coolant level, signs of moisture in oil (milky goo under oil fill cap)?
Any vacuum leaks resulting from hardened or cracked vacuum lines, or vacuum operated components?
I'm racking my brain as you've done a great job already tackling the usual suspects.
#15
Pole Position
When cold, the richer fuel air mixture could be masking a possible vacuum leak. Then, when the engine heats up, the leak could cause a "too lean" condition.
Just spit-balling here. Good luck!