1993 Grand Marquis - terrible idle. - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

LunaVyohr · 11-19-2010, 15:45

My car has a couple serious problems. First of all, when it's been sitting for more than seven hours and I go to start it, it will want to die immediately when it starts. I have to feather the throttle for about six-seven minutes before it will idle without dying.

Secondly, it idles very roughly. When it's been sitting for ANY period of time, even just at a stop light, it will start to idle very roughly, slightly jerky. The idle will often go from slightly normal to badly low. When I start it after it's been off, even for a few minutes, if I try to set off with it without revving it for a couple minutes, I'll have basically no throttle response, and the engine will jerk badly. I have to mash the accelerator, and it will act like fuel isn't getting into the cylinders. Often, it will also make an alarming popping noise from under the hood. I'll have to keep the accelerate mashed for a good 5, 10 seconds before it will pick back up and smooth out.

What's the source(s) of my problems?

**87_Crown_Vic** · 11-19-2010, 16:05

when was last time car had plugs and wires? also fuel filter would be good thing to do ... those are things i need to know... and if that stuff is current, i would be guessing the IAC is gummed up with oil and gunk and needs cleaned

LunaVyohr · 11-19-2010, 16:11

Just changed the fuel filter. Wires are good, plugs I'm not sure - if the state of the wires are to be believed, they are good as well but I haven't checked them.

LunaVyohr · 11-19-2010, 16:54

I should mention that when I'm revving it, trying to get it toidle without dying, sometimes I'll feather it a bit and when I let off, the throttle will stay as if I'm still revving it. Could one of my idle problems be a vacuum leak?

**Bert** · 11-19-2010, 17:17

As 87_Crown_Vic mentioned, the IAC could need cleaning. Unplug the MAF and see how it runs too.

LunaVyohr · 11-19-2010, 18:06

What's the best way to clean an IAC?

**87_Crown_Vic** · 11-19-2010, 19:18

i have used carb cleaner to clean it out... i spray some in the IAC and plug the holes with my hand and shake it up good... i dump it out then spray it again to rinse what didnt pour out after shaking