Will crank, won't start

Hello, I’m Pete from the Car Genius team at RepairPal. I’m sorry you’re dealing with this concern on your 1998 Buick Lesabre. Based on the information provided it sounds like you had an upper intake replaced as well as the throttle body cleaned and since then the engine cranks over and will not start. It does also sound like you have spark at the spark plugs as well as fuel at the schrader port. I recommend having a few spark plugs removed next to see if they are wet, this model had a concern with the EGR stove pipe melting into the upper intake causing coolant to flow into the lower intake flooding out the cylinders. A new EGR stove pipe has been released in smaller diameter to prevent this from occurring again and should have been replaced when the upper intake was replaced. If the plugs are wet with coolant I recommend removing all plugs and disabling spark and fuel and then crank over the engine to blow out the coolant from the cylinders, then clean and reinstall the spark plugs to see if it starts and runs again. If the spark plugs are dry the next thing to check is to see if you have fuel injector pulses, a loss of fuel injector pulses can indicate that the ignition control module (ICM) has failed and may need to be replaced. One other thing that comes to mind is the large brake booster vacuum hose at the back of the upper intake, this plastic fitting was common to break off causing a large vacuum leak which can cause this concern as well. If these all appear o.k. or if you are unable to look into these yourself I recommend having a certified shop look into this concern to help pinpoint the cause so it can then be repaired properly from there. If you need more advice, have any further questions about your vehicle, or want to connect with one of our RepairPal Certified shop's near you, we’re here to help. Just give us a call at 877-913-1554 where we will be happy to assist!