Northstar Engines and System Technical Discussion Discussion, 99 sts running rich in Cadillac Engine Discussion; i have a 99 sts that is running extramly rich when i start it up it will kick out a ...
99 sts running rich i have a 99 sts that is running extramly rich when i start it up it will kick out a cloud of white exhaust that smells like gas,will also do that when accelartion from lights. have been searching site an from what i have read it looks like a plenum leak could it be anything else were should i also look
Re: 99 sts running rich Remove the engine cover. Locate the Fuel Pressure Regulator on the rear of the fuel rail. Vacuum hose to the throttlebody.
Start the car and pull the vacuum hose off the regulator nipple. Raw gas in there ?? New regulator time. www.rockauto.com
Use a stethoscope to listen to each injector for a steady "tick-tick-tick-tick". If one sounds erratic or not at all, stuck injector. Junkyard or rockauto.
Air filter and throttlebody cleaning time ? Re: 99 sts running rich A plenum leak would cause it to run lean. Your '99 does not have a "plenum" (rubber coupler between the TB and the manifold). That came in 2000. Follow Subs advice.
have been searching site an from what i have read it looks like a plenum leak
Re: 99 sts running rich thaks sub just checked it gas pouring out will get replacemnt and replace it. let you know how it works