97 ZJ V8 JGC Wont idle when cold

Oct 21, 2006 4 Replies

Greetings,



My 1997 ZJ will not idle when cold.



It happened 2 weeks ago and we cleaned the battery terminals, checked grounds, and it all seemed good. After the cleaning truck ran fine. it has about 75,000 miles on it an i take good care of it.



But this morning it was about 37 degrees, and it wont idle unless you run it at about 1500 RPM.



After warming up , engine would idle normally. Have checked the alternator voltage, no codes appear other than the 55 code.



Any pointer appreciated, regards,



james



Excerpt from the '96 ZJ manual engine diagnosis 'Rough Idle"

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While not required a thorough cleaning of the throttle body assemble, Idle air passages, fuel system and injectors wouldn't hurt and only costs $12-$20 depending on brands and how thorough you need or want to clean.

billy ray is the man!! - Thanks

$10 - Poured in a bottle of fuel system/injector cleaner into a full tank of gas . Seemd a little better... $10 - Sprayed in TB cleaner and took it out for run on the freeway. Better yet... $80 - Picked up a new IAC Motor and changed it ( the old one was carbon city ). Sprayed a little TB cleaner in the IAC air passage and wiped out a lot of carbon from there. WOW..

It didnt run this smooth the day I bought it. Amazing, best $100 i ever spent on it.

Thanks Aga> Excerpt from the '96 ZJ manual engine diagnosis 'Rough Idle"

Thanks, I got the truck in 2000, its a 97, i figured a new IAC motor wasnt to gross an indulgance. How long a drill bit?

I will look up the Idle bypass port/Jet screw in the shop manual/Alldata. I am not a mechanic so things take a little longer:-)

thx, james

Will H> You could probably have saved $80 by cleaning the old IAC and the

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