Swapped injectors, now have surging at idle.

[markseven]

Those bolt holes do not go into the runners.

Dang. That would have been a quick fix...

Thanks man.

[ParsedOut]

Wait... You have to remove the hose that goes from the valve cover, through the runners and into the throttle body to take out the fuel rail. That one gets seriously toasty and brittle with age, I guarantee you that's your vacuum leak.

[markseven]

Wait... You have to remove the hose that goes from the valve cover, through the runners and into the throttle body to take out the fuel rail. That one gets seriously toasty and brittle with age, I guarantee you that's your vacuum leak.

Just ordered one... hope this is it!

[ParsedOut]

Hope so too, be sure to report back.

[markseven]

Fo sho... fo sho. Thanks man.

[ForcedFirebird]

That hose is easy to test with some brake cleaner. Did you re-seal the valve cover with fresh gasket and rocker shaft plugs? We keep breather hoses in stock at the shop, just for the above reasoning.

[mcr_driver]

Any updates?

[ParsedOut]

That hose is easy to test with some brake cleaner. Did you re-seal the valve cover with fresh gasket and rocker shaft plugs? We keep breather hoses in stock at the shop, just for the above reasoning.

I don't think he pulled the valve cover though.

[markseven]

That hose is easy to test with some brake cleaner. Did you re-seal the valve cover with fresh gasket and rocker shaft plugs? We keep breather hoses in stock at the shop, just for the above reasoning.

The valves were adjusted at E30 MotorWerks less than two months ago. Robert changed the RSPs, so I didn't change them again (mostly because I forgot to order them). I did put in a new VC gasket though. Are the RSPs critical in this case?

Any updates?

I did the test where you spray WD/40 at the base of the injectors. It felt like the engine stumbled when I sprayed second injector from the front. It didn't do it when I sprayed it a second time to confirm.

I don't think he pulled the valve cover though.

I did pull the VC.

[ForcedFirebird]

Robert covers bases like we do here. Surprised the crank case tube was old tbh.

Rocker plugs are good for a while, the oil hardens rubber, cover gaskets should have been fine if installed a year ago, passing a visual of course.

Have to trace the root of the change in hardware, and symptom.

[markseven]

Robert covers bases like we do here. Surprised the crank case tube was old tbh.

Rocker plugs are good for a while, the oil hardens rubber, cover gaskets should have been fine if installed a year ago, passing a visual of course.

Have to trace the root of the change in hardware, and symptom.

If I can't get it sorted out this weekend, it will be back at his shop asap.

[markseven]

Two things:

I was mistaken that M20B25 injectors are 17# units. They are 14.5#.

Due to extremely busy work schedule, I have not had time to remove and inspect the injectors / fuel rail, etc. and have been driving the car back and forth to work, keeping my feet on the gas and brakes when at a stop.

The result? It took about 75 miles of driving for the DME to adjust / calibrate to the higher flow injectors.

No more surging.

In any event, I do appreciate all you sharing your experience and advice.