Chevrolet Repair: Auto Repair, auto repair question, intake manifold gasket

Question
QUESTION: I have a 1998 Chevy Malibu Ls. I have a 99 engine in this car though. The engine cranks excessively before it starts. The computer reads P0300 and P0420. The engine jerks when applying gas after braking to a complete stop. Any idea what could be causing these issues?

ANSWER: Hey,

Sounds like a spark plug, ignition wires or ignition coil.  The P0300 is a missfire multiple code and the P0420 is EVAP.

Wayne


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QUESTION: I have changed the spark plugs and wires. I fthe misfiring continues then it will be the ignition coil? What can be done about the EVAP? I also noticed an oil leak today and it seems to be on the left side underneath the power steering fluid bottle. Would that be the gaskets?

ANSWER: Hey,

 Has the intake gasket been done on it recently?

WAyne


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QUESTION: There was an antifreeze leak which was repaired a couple of months ago. If I remember correctly it was leaking from the intake manifold gasket. Then there was an oil leak towards the back of the engine and that was repaired. Now it is leaking oil again right under the power steering bottle. One mechanic has looked at it and said it was the gaskets but he said not to worry about it but I don't think that was good advice coming from a "professional".

Answer
Hey,

 The reason I ask is because I have seen a flood of these engines recently with the same symptoms you have.  What happens is if the intake was done the rocker bolts have to be removed because the push rods go through the intake gasket.  Too many technicians are just 'tightening' these rockers down when they put it back together without using a torque wrench.  If they over tighten it (which is easily done) The aluminum threads (8mm) in the head stretch a bit and cause the rocker bolt to start coming out because of the extreme pressure on it when it is running.  You need to check the compression make sure the rockers are not coming out.  I have seen it at least 3 times in the last two months.

Wayne