1994 Saturn SL2 • 20,000 miles

My SL2 has a problem when I hold the gas in slightly at idle, it feels like it's missing very slightly, I believe either a compression or injector problem, and when I am driving, if I'm just coasting between 30 and 45 mph it acts like I'm moving the accelerator in and out a bit. It acts fine when accelerating, even lead footing it.

The only changes I have done recently is a K&N Air filter with an aftermarket air pipe to the throttle body to reduce drag, and Pulse Plugs, I forget the brand, but they gave me a noticeable increase in power and mileage, and emissions tested very well with them, does not burn oil, and they all spark very hot still.

January 17, 2012.

Are you using the oil wit the K&N? It's been found that filter oil can damage Mass Air Flow Sensors and Manifold Absolute Pressure sensors.

You should also check for a vacuum leak. And do a compression test.

Jan 17, 2012.
Just to add to this one I have only seen that k and n oil effect was mass air flow sensors which that car doesnt have it has a map sensor. Have you checked your coil towers where the spark plug wires go on for being corroded?Also have you checked your coolant temp sensor the bottom one with two wires going to it?Its really common for those sensors to go bad and cause surging on that engine. Also inspect the inside of the coolant temp sensor if the terminals are green or blue instead of silver you will need a new connector also.

Jan 17, 2012.
Good advice from the master.

Jan 17, 2012.
Thanks 4 the quick reply I called the dealer ant I was sent the wrong 1 they sent me the top thety reordered the correct ect sensor # d the with
2 wire connector ill try this he said the coorect number is 21025106.

Nov 12, 2012.
Yes that would be the correct part number which is the bottom coolant temp sensor with two wires going to it. Also inspect the inside of the connector if the terminals are green or blue instead of silver you will need to replace the connector also.

Nov 13, 2012.