guys,

i drove my wife's '02 escort to work today, and it has developed a bad vibration at idle. i haven't driven the thing in about 6 months, so i hadn't noticed. anyway, it gets worse when the a/c is on, and smooths out when slight throttle is applied. i can't feel it at all at cruising speed.

so what is up? the ecm hasn't set any codes. can i just advance the throttle a little bit so that it idles slightly faster? the car has no tach, so what should i shoot for as far as idle rpms, and how fast is too fast? should i just increase the idle speed until it smooths out?

one final thought. i have a slightly heavier oil in the engine right now (10w30). could the thicker oil cause the engine/oil pump to work harder, thus causing the vibe? i have always changed the oil with 10w30 (about 72k miles) and haven't noticed this before.

thanks for the ideas.

-matt

 

Well I'd try the normal stuff we do to out trucks first. Does it have and IAC thing? Is it clean? Are the ports? How old are the plugs and wires?

 

Try some acetone. It sounds dumb but it worked on my truck. You put about 3 ounces per ten gallons of gas for about 2-3 tanks. Mine truck idles smoother now than it did at 24k when I bought it. If take my hands off the wheel at a red light, I literally cannot tell it is running. From what I been told and read, that acetone is the main ingredient in commercial decarbonizing additives. Flame me if you feel like it, but it did work.

Of course this will not replace regular maintenance. You may need to replace plugs and wires, and clean out the TB/EGR, ETC..,,,,98