as if the oil mixing with coolant isn't bad enough for me to deal with now, i have noticed my car does not seem to accelerate like it used to. not necessarily missing like a dead cylinder, but just obviously slower, almost a hesitancy to accelerate.

car has new fuel filter, spark plugs, cap, rotor, air filter (all OEM) within 6000 miles. i checked compression last week - 205-215 psi on all cylinders (thought the head gasket might be bad). thought it might be bad gas but the problem persisted after a refill.

any ideas? clogged cat? bad O2 sensor? bad DME? DME relay?

thanks

 

All of the above or none of it. Could be the spark plug cables shorting out to the hood. Could be a dead injector.

Pull a connector off of one injector at a time while it's running. Tell you real quick if one is bad.

If it's a bad DME relay or DME the engine usually does not start.

 

we had a similar problem on the NA, the sprak plug wires were arching and it resulted in lots of power lose. I would check you wires and make sure they arent arching on things such as the hood and intake manifold.

 

open the hood at night and rev the engine. look for blue sparks where the wires pass close to anything metallic. If the cat is clogged the eng. should rev really flat even with no load, should feel soggy, not crisp and responsive

 

i see no sparks or arcing of the spark plug wires at night.

it might help to mention that the acceleration (or lack of it) feels exactly the same as when you start the car first thing on a cold morning, and it's hesitant to accelerate until fully warmed up. this is exactly how it feels now, even when the car is fully warmed up

 

Try filling an old windex bottle with water and spray the ignition wires at night with the engine running. They may not be arcing to their surroundings but to themselves, this may otherwise be hard to see with no load and at idle.

 

Also, check/adjust your fuel mixture.

 

If the ignition system checks out then my opinion is it sounds like the cat is clogging up. Several years ago the cat clogged on my 928 and the acceleration went way bad. Some girl in an escort raced me off the line and I LOST. Got a new cat put on and it was instantly like a new car. I seem to remember the sound of the exhaust gets quieter and more whoosh like when it is clogged (I assume because the velocity of the escaping exhaust is higher making a whoosh sound). A muffler shop can do a back pressure test to see if the cat is bad before you spend $$$

 

Hmm, I should get my cat checked as well, then again I only have 125psi on my best cylinder =(, but still my exhaust sounds like it's coming through a tiny hole, and I have alot of exhaust noise around the cat.

Could be the O2 sensor, check your fuel pressure. My car is outright sluggy, but my fuel pressure is almost 40psi, so it's definately running too rich, check your plug condition to see if you have the same problem, or perhaps it's too lean instead, but it'd run hot if it was.

 

I had poor performance with a bad O2 sensor. After changing it, things were more alive.

Bosch Universal 13913