Contour Enthusiasts Group Archives Forums General Troubleshooting Misfire Problem/Compression Test

My car is having an intermittant stuttering problem. When I'm sitting at a light and the engine is idling, once and a while it feels like the engine misfires. You can feel a slight shake thoughout the car. It just does it for a split second... almost feels like one cylinder either doesn't ignite, or ignites too soon.

I decided that it could be the spark plug gaps. So I pulled the plugs out and re-gapped them. I also took note that the tips on all 6 plugs were identical, having some slight carbon build up around the base of the thread, and then a kind of white tint on the electrode. Before I reinstalled them, I thought it would be a good idea to do a compression test, just to see the condition of the engine. I was anticipating even numbers across the board, but was I ever wrong...

First cylinder: 195psi. Sounds about right for this engine.
Second: 160psi
Third: 165psi
Forth: 185psi
Fifth: 155psi
Sixth: 180psi

What the heck! This engine only has 175,000kms on it, and its an automatic... so theres no way the engine could have been worn out or been over-revved. My 230,000km Mazda engine in my Festiva has 155psi across the board. Factory spec is between 130-160psi. That engine is 17 years old, has had the crap driven out of it at the track, and is turbocharged. I think its pretty bad that my 8 year old Ford Duratec is in worse shape then my 17 year old Mazda. I wish Ford would have stuck the Mazda KL series V6's in these cars like they did with the Probe. Not saying the Duratec is a bad engine, I'm just saying that I think the KL is more reliable and a better design. No faulty PVC system, no DPFE sensors to mess things up, no timing chains guide to wear out... etc etc etc. Sorry for the rant, but I'm just really disappointed in this engine.

Has anyone had any similar experiences with their compression test? Any ideas on what my hesitation problem may be caused by?

The rule of thumb for compression testing is that the lowest cylinder shopuld be no lower than 75% of the highest cylinder. Your engine is well within. 75% of 195 is about 145, and you are well above that.

Unless you can establish that there is a miss that matches the low cylinders, look elsewhere.

My contour has suffered the same problem. I instantly changed my wires and plugs, the plug condition was fair. I left the gap alone straight from the package, plugs were done first. The missing did'nt improve so I continued to change the wires. I know that the SVT engines run fairly hot and the wires are more likely to breakdown. Once this was done it was like driving a diffrent car. If your going to change plugs don't leave the wires, chances are you'll end up going back in later to change them.



'98 Contour SVT
'92 SHO