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N* install and plug question

deadsnake said:
150 across the board minus 4 and 6 105 in 4 and 125 in 6
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Busted rings or valve issues.

Run some SeaFoam through it if you haven't already. Some people have carbon buildup on the valves and the SeaFoam seems to cure it. It's worth a try.
 


If it's naturally aspirated then just dump it in the master cylinder vacuum line. You'll have to keep the RPM's up though so it doesn't stall.
 
It's the large neoprene line that goes from the back of the UIM to the brake master cylinder power assist.
 


Did you put SeaFoam in the oil yet?
It might just be sticky valve guides.

A cylinder leak down test may tell you if the rings are bad.
 
three causes of leakage are: head gasket, or either valves. head gasket is pretty easy to rule, out. in that case, you would be looking most likely at bad valve seals.
 
No idea still... replaced the module and it drives better but still misses... i hear a pretty bad backfire in the cat...could it be clogged? would it make the car drive like this?
 
deadsnake said:
No idea still... replaced the module and it drives better but still misses... i hear a pretty bad backfire in the cat...could it be clogged? would it make the car drive like this?
Click to expand...

A clogged cat would cause P0300 Random Misfire and it wouldn't have any power in the higher RPM range.

You've already established that there is bad compression in 4 and 6. You have to either do something to restore compression or remove the head on that side of the motor.

Another thing I would try is put 2 ounces of SeaFoam right in the combustion chambers (4 and 6). Remove those 2 spark plugs and insert a piece of 1/4 inch tubing and inject the SeaFoam. Let it set over night. This will wash the oil from the cylinder walls. Before startup, crank the engine without plugs in and ICM disconnected, then put some 30W oil in the cylinders 4/6 and repeat. Reinstall plugs and reconnect ICM - start the engine.
 


You may want to pull the valve covers off and check for a loose rocker.
Do the SeaFaom thing and see what happens.
 
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