So I noticed the oil cap was being sucked to the valve cover while checking the timing today. Is this normal. I'm have trouble with a ruff idle and small back fires in exhaust. I have not messed with timing and it checked within spec. I replaced 3 injectors to known good ones. I'm lost. Also car revs to about 3-3500 and then boggs.

 

What year/engine? The PCV system needs to have a fresh air inlet at some point to allow ventilation of the engine and not just vacuum. The inlets are different for different engine types. Anything with a MAF needs to place the inlet after that MAF so the air is measured.

 

It's a 88 Trans am GTA. 5.7l 350ci, tpi

 

That would be a MAF setup.

Your PCV system should be: from the port on the TB between the throttle blade and the MAF (the one with no vacuum), to the pass side valve cover with no PCV valve or obstruction; and from the driver's side VC, with the PCV valve installed in it, to the port on the TB (behind the throttle blade) that has vacuum on it when the engine is running.

I doubt the PCV system has anything to do with popping in the exhaust or "bogging"; but it can DEFINITELY cause idle problems. Sort the PCV out first by connecting it as described, then put a new set of spark plugs in it to fix the popping in the exhaust, then go to work on the other.

 

Thanks for the advice. New plugs and wires already tho.

 

Ummmmm.... so???

Popping in exhaust = misfire, allowing raw fuel and raw air into hot exhaust system

The evidence speaks for itself, can't deny the FACTS

"New" isn't necessarily the same thing as "working right"

Change the plugs. Since you mention new wires, check the firing order CAREFULLY: esp #5 & #7. Very easy to make that mistake.

But, fix the PCV first.