Bad lower intake manifold gasket?

[35Remmy]

Stopped by Advance today and borrowed their scanner to run my codes...even though my check engine light WASN'T on...sure enough, pulled a PO300...multiple cylinder misfire...not sure if this is related to pinging or an old code or what...engine seems to run fine, it idles fine.

In any case, I think I have a bad lower intake manifold gasket (great compression, but unexplained loss of oil, pinging (perhaps because of ingestion of oil because of bad LIM gasket, and cylinders 4, 5, and 6 with oil on the threads of the plugs.

Shouldn't I be getting bank 1 or bank 2 lean condition codes with a faulty intake manifold gasket?

I want to be at least 90% certain before I start pulling things apart!!!

 

[James909]

I had symptoms very similar to yours. Pinging at highway speed and oil consumption, but other than that the car ran perfect. I have a first gen so I am not sure if this solution will work for you, but at the recommendation of wood1 I bought an inch pound torque wrench and tightened the lower intake bolts. The middle ones were so loose that I could back them out by hand. Now the pinging is gone, however I only did this on Sunday so it's too early to tell if oil consumption slowed down. I'm not sure if you can reach the lower intake on a second gen without taking the plenum off but if you can reach them you might want to try torquing them. Even if it doesn't cure the problem, if the pinging and oil consumption is reduced than it is very likely that it is the gasket. Also, I had no CEL, granted the OBDII computer is more advanced but it's possible that either the air leak isn't bad enough to set off the CEL or like in my case, I'm pretty sure that my intake wasn't leaking air past the gasket, only oil which was causing the pinging.

Was the code that came up during the test a continuous memory code or did it appear during the test?

 

[35Remmy]

JAMES...My CEL wasn't on, but I scanned the engine for the heck of it, and brought up the PO300.

I always thought that if ANY codes were stored the CEL would come on.

I'm not sure what a continuous memory code is.

 

[James909]

Sometimes the computer will store less severe codes without out setting off the CEL.

A continuous memory code is just a code that is stored in the memory.

 

[35Remmy]

Oh, ok...see, I was thought that ANY code would trigger the CEL. Thanks James.

 

[ThePhoenix]

it might trigger it but not keep the light on...I had it flash, then be off, yet the code was stored