My idle runs rough and it fluctuates rpms. Its not steady. So far I‘ve clean my throttle body plate, put bars liquid copper stop leak for my intake manifold, replaced my ma‘s air flow sensor, pcv valve, egr valve. Runs better with a new gasket on my egr valve. I took it to auto zone and it doesn‘t misfire anymore. Aether I have a vaccum leak somewhere or my aic, map or my tps are bad. The lady said the wiring could just be bad and I would need to fix it. I can‘t spend a lot of money because I already have stuck a lot of money in the 5.3 allready. I‘m 17, I‘m stressed out about this and I need some answers. My stock air intake duct is caved in. Idk if that can have any affect on my idle performance or not. Answers?
Sounds like you need intake manifold gaskets. They sell updated ones now for your truck that last longer. Get some propane and with the engine running put it along the intake manifold to see if the idle changes. Bar's leak isn't going to seal an intake manifold gasket vacuum leak. But it will stuff up your cooling system. Also could be a fuel pressure regulator. Pull of the fuel pressure regulator hose and look for signs of raw gas. And thirdly have a cylinder leakdown test performed to check for internal engine problems especially on high mileage not properly maintained engines. Good luck and hope this helps.
What are the code definitons for po449 and po507why did you put the stop leak in your cooling system did you think clogging up your cooling system would make it run better.with your air intake tube damaged it could be pulling air past the MAF which could give you drivability issues
