Fuel pump or alternator bad?

[mscally07]

I have a 2005 grand prix gtp: SO when driving home from work last night, my car started bogging really bad. RPM needle was going nuts, dropping and raising uncontrollably. Car still runs but drives but its seems like its going to stall when the needle drops sometimes. My brother has the HP tuner so we are going to run it to see what it diagnoses the problem to be but am still curious to what you guys have to say about it. And if it is the fuel pump, should i drop the tank or is the access panel good enough to remove the in-tank fuel pump to swap old for new. Any help would be appreciated and its my daily driver so i hope you guys can help me get back on the road.

[cerick08GP]

Well, it sounds like the crank position sensor is failing to me.
Good luck

[quinnp12]

Based on past experience with a different car, it might be simpler than that and just be clogged fuel filter. Worth taking a look at and much cheaper.

[mscally07]

Whelp, ran the HP tuner to see what came up... said the MAP sensor was done. Ended up being from boosting, shot the vacuum line off in 2 places. Bought a new fuel pump for nothing. Thanks for the input

[cerick08GP]

Those MAPs are sneaky they don't go bad often. Just another proof positive scanning is very effective trouble shooting tool.

Glad to see you're all fixed up