Greetings everyone, I'm having some slight problems with my '87 GM. When at a stop light with the A/C on it starts to have a rough idle.. This problem can be cured by turning the A/C off or shifting into Neutral... From researching I'm guessing it's the MAP sensor. Could someone confirm this & give me more info on this issue(BTW I'm no car savvy mechanic)? Also I don't know if this is related to the same problem but when shifting from reverse to drive or vice-versa the car reallly dies down, and 1 incident cut off on me.. My guess is some sort of vaccuum hose... Thanks in advance for the help...
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@Ryan.Madison68 -
A crapped up IAC could cause a rough idle, and the A/C being a large load on the engine would make it really low if the PCM can't raise the idle with the IAC being dirty. -
What he said.
Related, when was the last time it had a tuneup and a fuel filter?86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousersComment
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I just had a new IAC installed last fall... but anywho how would I go about cleaning it? I changed the spark plugs, wires, and fuel filter about 6 months ago...@Ryan.Madison68Comment
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clean the throttle body too.
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cleaning the IAC: on the car... open the throttle all the way and hose out the ports to the IAC in the side of the throttle body with throttle body/carb cleaner (engine off of course).
off the car: same thing... hose it out. just remember to replace the gasket as well.
I generally use the "on the car" method.
This too. get all the black gunk (if any) around and on the flapper (real technical term there) in the throttle body.Originally posted by jayh View Post
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
rides: 93 Crown Vic LX (The Red Velvet Cake), 2000 Crown Vic base model (Sandy), 2003 Expedition (the vacation beast)
Originally posted by gadget73
... and it should all work like magic and unicorns and stuff.
Originally posted by dmccaig
Overhead, some poor bastards are flying in airplanes.Comment
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OK I sprayed the air intake/ throttle body cleaner around the throttle body and air intake but the problem is still persistent... Although the cleaner did help with calming the startup idle abit... Any more suggestions or solutions?@Ryan.Madison68Comment
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DO NOT USE CARB CLEANER IN A THROTTLE BODY!!!! That just makes stuff worse, there's a protective coating on the throttle body that's supposed to limit the amount of gunk that builds up there.
Anyway, have you checked for any codes? If there are any, they might be able to point you in the right direction.Comment
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How low is your idle speed? Wore out engines idle slower if they have never been adjusted.1989 Grand Marquis LS
flat black, 650 double pumper, random cam, hei, stealth intake, Police front springs, Wagon rear, Police rear bar, wagon front ,exploder wheels, 205/60-15 fronts 275/60-15 rears, 1 5/8" headers, 2.5" offroad x pipe, Eclipse front bucket seats, Custom floor shifter, 4.10 gears, aluminum driveshaft and daily driven. 16.77@83mphComment
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There is no idle adjustment on an EFI car. Its set by the computer. That screw is a throttle stop, not an idle adjustment. CFI and carbs have idle screws, not multiport injection.86 Lincoln Town Car (Galactica).
5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley
91 Lincoln Mark VII LSC grandpa spec white and cranberry
1984 Lincoln Continental TurboDiesel - rolls coal
Originally posted by phayzer5
I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousersComment
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