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Discussion Starter #1 (Edited)
I own a 2002 Corolla and the check engine light says it's code P0302 which is an intermittent misfire on cylinder #2.


I've changed all the spark plugs, the air filter, swapped the coils and fuel injectors around to see if the code changed indicating different cylinder. NO SUCH LUCK!



A compression check revealed a psi of 110, 30, 110, 110 on cylinders 1 through 4 respectively. Possible causes are a bad intake valve, exhaust valve, or broken or stuck rings due to varnish build up. The car is not burning any oil and has no smoke from the exhaust pipe, etc.


I have found a loose wire and plug with no wires going to it on the right rear of the engine. The plug is on a bracket held on by the right rear valve cover bolt. The wire exits the wiring harness where the wires going to the coils for the spark plugs exit.



The loose wire is tiny and black with a white stripe along its length. The plug is oblong, about 1/2" wide by 3/8" in height. There is a rectangle in this that has two round rubber tubes in it, one is black and plugged up, ie, no hole for a wire, and the other tube is a dark blue with a tiny hole that the twisted copper wires from the loose wire could be forced into. The problem is that the plug doesn't have any wires attached on the back end!


My question is.....could this loose wire and strange plug have anything to do with my intermittent misfire problem?


I would attach pictures but the way to do that on this site totally escapes me !


Help!
JON L. WHITE,
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I own a 2002 Corolla and the check engine light says it's code P0302 which is an intermittent misfire on cylinder #2.


I've changed all the spark plugs, the air filter, swapped the coils and fuel injectors around to see if the code changed indicating different cylinder. NO SUCH LUCK!

A compression check revealed a psi of 110, 30, 110, 110 on cylinders 1 through 4 respectively. Possible causes are a bad intake valve, exhaust valve, or broken or stuck rings due to varnish build up. The car is not burning any oil and has no smoke from the exhaust pipe, etc.


I have found a loose wire and plug with no wires going to it on the right rear of the engine. The plug is on a bracket held on by the right rear valve cover bolt. The wire exits the wiring harness where the wires going to the coils for the spark plugs exit.



The loose wire is tiny and black with a white stripe along its length. The plug is oblong, about 1/2" wide by 3/8" in height. There is a rectangle in this that has two round rubber tubes in it, one is black and plugged up, ie, no hole for a wire, and the other tube is a dark blue with a tiny hole that the twisted copper wires from the loose wire could be forced into. The problem is that the plug doesn't have any wires attached on the back end!


My question is.....could this loose wire and strange plug have anything to do with my intermittent misfire problem?


I would attach pictures but the way to do that on this site totally escapes me !


Help!
JON L. WHITE,
Pastor
Hello JON L.

If I'm reading your post correctly all cylinders read 110 lbs except no# 2 which reads 30 lbs?
Don't know about the wiring issue you mention but any cylinder with only 30 lbs compression is definitely cause for a misfire.

Rich.
 

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No that device sounds like AC idle-up valve. Not related in any way to your misfire. That's caused by some mechanical problem inside your engine. There's absolutely zero way anything outside engine can cause that low compression number. To fix, you'll have to crack open engine to find broken part and replace it.

Don't get cause and effect mixed up. I have metaphor using water on kitchen floor i can use to explain if needed.
 
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