My car is having rough idling at stop signals but feels ok at cruising speed, though fuel economy has been bad. I got oil and spark plugs changed today but still no difference. I want to get the OBD check but all auto part stores seem to do that for post 1995 models. When spark plug cables was pulled out from the wells, oil spilled out from one or two wells. Not sure whether it is a gasket leakage or piston ring problem. Is rough idling is related to this or something else? Please advice.
Rough Idling - Bad fuel Economy on 1994 Nissan Altima
by Visitor in Houston, TX on March 13, 2010
ANSWER by baddawg , July 07, 2010
Your valve cover gasket is leaking oil into the spark plug wells thus causing your engine to idle rough & have bad fuel economy, If you are do-it-yourself, you can go to an auto part store to get a replacement valve cover gasket (which should include the spark plug well gasket) and get some form-a-gasket paste. Also you need to replace the spark plugs and spark plug wires since they are soaked with oil. First to cool you engine down and mark your firing order on the distributor cap (remember 1 at the timing chain end). Disconnect the valve cover breather hose from the air cleaner hose. Then remove the valve cover and remove the old gasket and form-a-gasket & remember to keep the nuts. Clean up as much of the oil from the spark plug wells with the spark plugs still in and clean up the oil from the valve gasket areas. Remove the old spark plugs and clean up what oil is left in the spark plug wells. Replace the spark plugs with new ones and tighten properly. Put a thin layer of form-a-gasket on the areas where the valve cover & spark plug well gasket will contact. The put some some form-a-gasket on the valve cover where the valve cover & spark plug gasket will contact and then put the valve cover & spark plug gasket on the form-a-gasket so the form-a-gasket will gaskets in place while you put the valve cover back on the engine. Remember to tighten the valve cover nuts finger tight first and then proper sequence & torque. Replace the spark plug wires to the spark plug and connect to the distributor in the proper position. Check you engine oil level and add oil as needed. Start your engine and check for oil leaks.