Chevychick
TYF Newbie
I have P0171, P0174, and P0305 on my 99 Tahoe. I know the P0305 is misfire in cylinder 5 and I know that P0171 and P0174 are system too lean bank 1 and bank 2. I have been smelling coolant and my question is could a bad intake manifold gasket cause these codes? The truck also struggles going up hills with steep grades and I feel the misfires. Fuel pressure regulator was changed after I got a P0300 code and that code hasn't come back, distributor cap and rotor were just replaced, ignition coil was just replaced as well. Mass air flow sensor is new, fuel pump was installed in 2019/early 2020. 3 of the 4 O2 sensors have been replaced. Plugs and wires are fine. I don't want to just start throwing parts at it, I want to be able to fix it once and for all. Any insight would be much appreciated. This is the newest vehicle I've owned, I'm used to my 88 K5 I had or the 86 Monte Carlo SS and 84 Camaro I have lol. Thanks in advance!