I have a 99 grand prix GT with 197,000 miles on it and it has gotten to where is spins over about 20-30 seconds before it fires up. i changed the fuel filter and spark plugs and wires last night, and it still idles rough and hard to crank. i checked the fuel pressure, 42-43 lbs at idle and it goes to 50 lbs when i unhook the vacuum from the regulator. i changed the coil the #3 spark plug wire is on a week or so ago because it has rust on the tower. any ideas on what i need to check next?

clean ur MAF sensor.

would the MAF cause it to be hard to start? the old spark plugs were red on the electrodes, what does that mean? i ran some 104+ octane boost in it a week or so ago to help clean the injectors.

The red on the electrodes could be from fuel additives; this is an older spark plug chart but you get the idea: http://www.autolite.com/pdf/PlugTips.pdf

I would try cleaning the MAF first, also.

as far as i know octane additives can be very hard on the engine

the octane boost is what colored the plugs red. i sprayed some parts cleaner on the MAF but it hasnt helped the hard starting issue. any other ideas?

maybe vaccume leaks some body else could probably help more but if you can hook it up to a scanner and see what all the sensors are reporting it might help track down the problem

when my cat started going out i noticed lack in milage and only found out it was the cat cause the vaccume at idle was very very low

the cat was doing its job but starting to clog

i cleaned the MAF and it is still hard to crank. the scanner says misfire cylinder 3 and a weekago it said multiple misfires. in the past it also said evap small leak. the idle is a little better. i dont understand the #3 misfire, i replaced the coil and plug and wire on that cylinder already. any other suggestions? maybe the fuel pressure is leaking down.

Did you change the plug?

Could be the injector.

check all the wires to the injectors
and check the plugs

yes, i replaced the plug and wires on all cylinders. even replaced the coil for #3 because the tower was rusty. could it be the injector?

if it was me id move the injector 3 to say cylinder 1 and see if the missfire follows

be VERY careful with the upper and lower o-rings

I only asked about plug because you didn't mention it earlier. I'd do as amcs recommends. Only while your at it you might want to get new orings instead of re using the old ones.