Pontiac Repair: 1997 Pontiac Bonneville wont start, fuel pressure regulator, pontiac bonneville

Question
My 1997 Pontiac Bonneville was running rough so the mechanic read that the coils were bad and replaced all 3.  He told me that the plugs may have fouled.  It ran better, but still a little rough.  Replaced plugs and plug wires.  Now it won't start.  Also reset computer by removing positive lead from battery.  Help!  Any suggestions?

Answer
Hey Patrick,

Well first off I find it hard to belive it needed all three coils.... On that engine a things to check. Why did the plugs foul? My guess is that you more than likely have a fuel pressure regulator that is leaking fuel into the vacuum hose. It may have been a small leak at first but as the diaphragm has gotten worse in it the leak has also become worse.. Did you fuel economy drop when this happened as well? If that were to be leaking really bad it could cause a no start and cause the engine to flood.. If you mechanic has a scan tool when it does finally start to run you can see exactly which cylinder or cylinders are misfiring. As for it not starting right now??? You can get a spark tester and see if you have spark at all 6 plugs. Another problem with these engines is plugged/clogged fuel injectors. I doubt it would cause a no start but a rough idle for sure.. You could have a engine sensor that's sweked out of it range making the computer want to run the engine way too rich or way to lean and it not start as well. I assume that when you say it will not start that it cranks over okay.. If it will not crank over then you may have a whole nother issue with that engine that's pretty common. The upper intake manifold is made of a composite plastic and the rear of it warps and it allows coolant to leak into the engine's air intake system and fills the cylinder up with coolant causing the no crank. If it a small enough leak it could also have caused you fouled spark plugs..... make sure the radiator is full and the overflow bottle as well. Sorry I can't be of much more help but those are the obvious things to look at.... Good luck :0