cold idle issues

LewmaticDC2

New Member
when i start the car it feels like its backfiring and when i look at the back the muffler shakes while this is happening. the tach would bounce like its struggling to keep steady power, but when its warmed up it stops and idles is fine. car drives fine but this happens only on cold start ups. i've changed the spark plugs and wires and use fuel injector cleaner but it still continues. no loss of power or hesitation while driving. what do you guys think? its a 94 RS with 122,602 miles on it
 
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AcurInteg96

Just call me chris.
when you start cold it should idle and 1200 or so. then it should slowly go down as it warms up. the muffler moving it just vibration from the engine. do you hear a popping noise?
 

LewmaticDC2

New Member
cant hear a popping noise but i can feel short puffs coming out the exhaust when i put my hand over it then it goes away when the engine is warmed up.
 
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AcurInteg96

Just call me chris.
its just the increased rpm. mine does the same thing.
 


gotgohan

Apprentice Mechanic
Yo.. keep in mind that a lot can have to do with your idle... Check air filter, check engine light on, check your antifreeze.. all can be a problem
 

AcurInteg96

Just call me chris.
Yo.. keep in mind that a lot can have to do with your idle... Check air filter, check engine light on, check your antifreeze.. all can be a problem
yeah i didnt think about that. i do have a CEL but mine did that even before my cat went out.
 

gotgohan

Apprentice Mechanic
well whats the codes? CEL stands for more than one code, another could have popped in. You have IAT sensors that might even mess with it too. I have seen LOTS AND LOTS of cars have a rough idle because of IAT, and a dirty airfilter... its a bitch


Check all those.. its not hard. How long has it been since you changed ur antifreeze.. I think its suggested every 50-100k miles to change it.. I just changed mine and my bad idle I had went from bad to moderate... lol theres still something making the car shake. but it does it all the time so I got a different problem..
 


AcurInteg96

Just call me chris.
i read codes and it just said catalitic failure. antifreeze changed with waterpump. air filter changed with tune up.
 

gotgohan

Apprentice Mechanic
Try cleaning out your IAT with Metal cleaner or carb cleaner. Maybe clean your throttle body too with carb cleaner. Anything can help
 

LewmaticDC2

New Member
ok i checked the distributor and the screw that holds in the rotor got loose and come off. so i screwed it back in and the car idles fine now. going to replace the rotor and distributor cap this weekend.
 
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