ZR8ED

Lately I've noticed that when the car is dead cold after sitting all day at work, or first thing in the morning, that the car starts up normally, but runs rough for a few seconds before settling out to a smooth idle. It had been fine for months. Well, I inadvertantly fixed it yesturday.

I had the intake apart to mod my afm (port matching, and smoothing out transitions and casting marks) When I had completed this, I gave the afm a thorough cleaning with compressed air, and lots of mild solvent to make sure I got all the aluminum dust out of it. ( I removed appox 1 shotglass worth of aluminum from the grinding process) I blew it all out again after it was dry, and then used copious amounts of solvent/cleaner to be super sure. I then wiped it all down inside and out (it DOES get dirty inside) "while I was at it", I cleaned the afm connector and harness and the temperature sensor (near/under the jboot). I also cleaned and detailed hard to reach areas of the engine bay, just to make it look nice and neat. I reinstalled, and wala! no more rough idle on initial cold start.
I'm sure it was cleaning the connections of the afm, and cleaning the inside of the afm and maybe even the temp sensor connector that solved this. (the port work would not affect this.) I'm just putting this out there for anyone who is experiencing a cold start rough idle. Clean your afm and connectors. Take your time, and be careful. The whole job including the porting work took just over 2hrs, with 1hr to do the port work (I have done this mod on my cab last year, so I knew just what to do.)

jcslocum

Thanks for this. We have a same/similar problem. It's always stumbling on cold start.

John_AZ

Thanks for the information.

A RL post & sponsor 944online suggests to just change the DME temp sensor:
https://rennlist.com/forums/924-931-...-troubles.html

John