I have an 85 Iroc with a built 350 TPI motor. The car idled and ran fine before I had the throttle body ported from 48mm to 52mm and I put bigger injectors on it, I went from 19lb/hr to 24 lb/hr. Since I did this it runs fine other than if it sits at idle for more than 30 seconds it gets really choppy and acts like it wants to die. The code it throws is "lean exhaust". Any suggestions or has anyone had this issue before? Thanks for the help!

 

Did you burn a new chip for the bigger injectors?

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Mods. GMPP Vortec heads, Comp Cams XR269HR, Crane Gold Rockers, Hooker headers, SDPC intake manifold, Edelbrock Runners, MSD Coil, Holley AFPR, free flow exhaust, Air Foil, TB Bypass, K&N filter.

 

This sounds like a tuning issue. have all of the connections been made correctly? How about a vacuum leak? And as stated above, you need the correct Eprom chip in it.

 

are the injectors you installed new or used?

 

There is a chip in it. It was in it before though. It is a hypertech. I have not had it tuned and I have done my best to track down any leaks. The injectors were used but they were all tested. Where could I find a chip that you are talking about? How much? Thanks.

 

Your chip does need redone. Not only will your IAC steps need changed, your fuel chart will be totally different now with different injectors.

 

These chips add more fuel (richer) so when you put in the 24 # injectors (25% bigger), you got a rich chip trying to run a larger (richer) injector. This makes for a very rich setup, it is a wonder that it even runs.