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84 Crossfire rough cold idle

6K views 5 replies 3 participants last post by  Goonboy61  
#1 ·
Hello,
I'm a new 'vette owner since 8/06. I've got an '84 Crossfire that has continued rough idle issues. I know, I know! Why did he buy a crossfire??? well, I believe that it's still a great car! Anyway, I've done so much to try and improve this idle. I had it professionally tuned at a Corvette shop using all new Delco parts; New wires,plugs, cap and rotor, pcv, fuel filter,ECM,TPS,MAP sensor, EGR, and last but not least, a new GM harmonic balancer as they told me it was spun. Now, it runs just a bit better (at least it doesn't cut off several times after starting like before) But, it still "chugs" along at cold idle and only slightly improves when warm. A few vacuum lines were also replaced with no resulting improvement. They told me "this crossfire will always run rough" ( which I don't believe that it should). After warm up when I hit the gas when driving, it does not respond well until I "step on it". I use 93 fuel and try to run it enough to get some new gas through the system. What else am I missing here?? HELP! Is it more vacuum leaks at certain areas? Any help would be appreciated.
 
#2 ·
I had an 83 Z-28 with cross fire and it was a PITA until I did two things: add a bottle of Red Line SL#1 fuel additive (used to be called valve and injector cleaner) every 5000 miles and use K&N air filters - - - and it all went away.

Main culprit was the damn injectors that would get dirty and foul like crazy and I must admit that this is one of two Red Line products I will use. Their oil is junk.
 
#4 ·
All I know is that REd Line SI#1 is THE injector/valve cleaner and that cross fires are very fuel pressure and air sensitive. If you don't have junk insulation under your hood, remove the air filters but let the housings on and drive a few miles - - it will tell you if it is the air/fuel.

the Redline will eliminate any possibility of dirty converters.

Me, I would look into the possibility of a double pumper Holley carb but don't know if it will work with the computer without a lot of false check engine lights.

Almost forgot: check the damn converter and make sure it isn't clogged as a clogged converter can mimic about anything -- perhaps it could be 'cleaned out'.