: Leaking Head gasket cause miss at idle?

05-31-04, 08:08 PM
Hello all,

New to the forum and to owing a 98 STS. I just got the car at auction with 72K on the clock. I have really enjoyed the car so far but I have already encountered some problems.

The water pump was leaking so I replaced that this Saturday and flushed the cooling system.

Also the engine had a miss at idle. First I ran a take of 91 with Chemtool fuel system cleaner, but no change.

I have read every post about idle or hesitation problems. After an inspection of the plugs and wires the appear to be new and a good shape. The plugs are the correct Delco gaped at.050, and the wires are aftermarket carquest brand. Note that 2,4,6,8 plugs were very clean and looked like new. I have only removed and checked # 3 on the starborad side becuase I saw that wire boot was not flush with the cam cover. It looked normal.

Fuel pressure regulator does not appear to be leaking when the vac, hose is removed. The #2 injector looks newer then the rest.

In a post from last year a member said that he his misfire turned out to be caused by a leaking head gasket, and that it was leaking just enough to cause the misfire at idle. After reading this I remembered how clean the plugs looked on the port side of the engine. I stated to think that I may have a gasket problem.

Can anyone give me some advice on this theory and how prove or disprove it?

I also found out today from reading the post here that I have a bad motor mount. I had the wife rev the engine in drive and the passenger front came up about an inch. Any advice here would be great also