Code P1128 '01 Tiburon

That is a lean code, and a big problem for Hyundai's cause so many things can cause it, first do the basics, replace the fuel filter, check for any vacuum leaks including the manifold and repair if you find any, if that didn't cure the code then it gets deeper into the engine control systems and you will need so special equipment to go much further. Do you have access to a live data scanner?

Yes, I am using a OBD scanner that I just bought but not sure if it is a "live" scanner? I do believe the car has an exhaust leak close to the manifold.

That will have to be fixed as it can have an effect on the O2 sensors and that relates to fuel trim, rich or lean.

I fix that and see how it goes. Thanks for your help.

Okay, I replaced the manifold as it did have a crack in it. It ran fine as always but today I sat in traffic idling for about ten minutes and the CEL popped up and it was the same code. Another issue is with it starting after sitting for about 20 minutes after shutting it off. It takes numerous tries to finally get it to fire up. Then when it does fire up, it sputters for a few seconds before reaching a smooth idle?

That sounds like a fuel vapor lock after a hot soak and that should not be happening with fuel injection unless then flow rate is too low, when was the last fuel filter change? Have you done a fuel pressure and flow test lately?

The fuel filter was changed about a year ago, but later on the fuel tank was cleaned but eventually had to be replaced. I have not done a fuel pressure test yet. I do have a new fuel pump to install and will change the filter as well and see how that goes. Do I need a special do to conduct the fuel pressure test? Thanks

A fuel injection pressure tester is something every tech has in his tool box, but you maybe able to rent one from your parts store.