Why won't it start?

go to repair shop urgently before its too late............

run the fault codes and look for injector problems and coil pack problems

Sounds like a head gasket problem.

You'll have to figureout if it is a fuel or ignition problem.Is the check enginelight on ?

my monterosport 2001 runs great till you come to a stop sign the rpms drop and it dies start it back up revs itself and rpms drop and it dies. we can start it up rev it and it clearsup and idles but later on when you come to a stop it dies again we have cleaned the egr valave and still same thing could the tps be the problem or what?

Disconnect the battery and let the computer reset. Do the issues go away? If so, then it is related to something that the computer is learning during driving. Narrowing that down can take a LONG time, even for a certified automobile technician.

Check your o2 sensor, do you have any CEL (Check Engine Light coming on?

First thing I'd do is replace the fuel filter. If the car runs fine on level ground or downhill but struggles uphill, it's usually because a clogged filter isn't allowing enough fuel through to satisfy the engine's demand for enough to keep you at speed going uphill. Try that out - it's an inexpensive part and is usually the cause of your symptoms.

try replaceing your temp sencer. some time they are near the goose neck or on the block ok . and see if your fan sencer is working. good luck

alternator maby needs to be changed, and check your battery