jkhall

New(er) to LS engines and troubleshooting is my weak area still.

I have an LQ4

• trick flow GenX220 fast as cast heads.
  • Yella Terra YT6645 roller rockers
• Howards cam model 196765-12
  • 228/234 @.05"
  • .604/.609" lift.
  • 112 lobe seperation
  • 108 intake centerline
• LS6 intake
• 36lb Fast 303608 injectors
• Hooker Super Competition Headers 2201
• New Wiring specialties LSx wire harness
• Setup as Speed Density
  

My idle is rough'ish fluctuating between 725-800RPMs. I have a P0200 injector circuit malfunctioning. My manifold pressure is also fluctuating 7-8lbs. there are no cylinder misfire codes

My thoughts are a leaking intake manifold gasket for the low manifold pressure. The Injectors are new and not sure how to test the injectors. Its a delphi harness with adapters between harness plug and injectors. was also thinking to go and get NOID light to test the harness through the adapter. not sure its necessary as I have no engine misfire codes. should I still do this step? tomorrow moring I also plan on taking my can of starter fluid and spray all vacuum hoses to detect for idle change (leaks).

What am I missing, or any suggestions? I am almost shooting in the dark here.

Picture of my car and engine added. thank you in advance.

G Atsma

If you suspect a manifold vacuum leak I would address that first. Pull the manifold and check all the O-rings. If suspected, put in new ones. Cheap insurance.