douglassimi

Installed another set of ccv valves today, along with new plugs and coils (plugs because i figured they would be junk with all the oil going through the motor, and coils because this car has had a mysterious gremlin with a misfire code every 6 months or so and a buddy at a dealership is hooking me up on parts right now, so what the heck, couldn't hurt). Again, car fires up and runs perfect when cold, then it starts to run horrible and the whistle appears, going to take a stop watch and time it tonight when cold, tomorrow in the am and tomorrow night, and see if the issue appears at the same or relatively the same time during warm up, like a system comes on line and that causes the problem.

Any idea where to look for a vacuum leak on this motor, as there are very few places it could be, both vent hoses are the new insulated style, and are firmly in place. The return line which attaches to the intake next to the throttle body is also firmly in place. When the air injection hose was replaced, the intake manifold gasket was replaced. the only other area it could be is in the valve covers, yet i have gone over them with a stethoscope and cant hear any sucking sound, and have sprayed bottles of carb spray over the intake and fittings and valve covers and not noticeable change, yet when you close the vacuum off to either valve cover by removing the spring under the ccv valve, the idle quality improves, and again, only codes being set are misfires on all 8 cylinders

Parts replaced so far.

Water pump and radiator hoses along with temp sensor in pump housing and lower rad hose, and degrease the engine, this is when all the problems started

Replaced the air injection hose assembly that runs under the intake manifold, clip broken on pass side valve
Replaced soft line from y hose to secondary air pump, precaution.
Replaced secondary air pump filter.

Replaced ccv valves TWICE.
Replaced both vent hoses to intake manifold.
Replaced upper and lower injector o-rings
Replaced throttle body gasket.
Replaced intake manifold gaskets.
Replaced Ign Coils and Plugs

mfrasca

Get someone to smoke it.

douglassimi

Did a test today, and started it cold and watched the temp, and time it took from a cold start to see the issue arise, granted not really cold out, 86 ambient, but it took 9 mins from start at only idle for rough idle to begin and the exact temp was 70c or 158f....will test again tomorrow and see if same results

stoic1

What ^^^he said. Get a reputable indy mechanic to run a smoke test on your vehicle. He will be able to narrow down where your car's problem is at.