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Frustrated and at a loss

S

snortysgple375

New member
I have a 2003 Pontiac Grand prix limited edition, recently I changed the crankshaft position sensor, all three coil packs, I installed new top of the line plugs and plug wires and I replaced the Catalytic converter, and I still have an issue with the tach jumping around and the engine just doesn't have the power to climb hills. I recently noticed that I can step on the gas and the speedometer takes about 1.3 seconds to respond! Any one out here in GP land have any ideas or helpful hints I would greatly appreciate the input....snorty
 


does it come on with the key on, engine off. just making sure that the bulb isnt burned out lol.

try spraying carb cleaner around the lower intake manifold and see if the idle changes
 
all the lights come on when the ignition is switched to on and the they go out after car is started, while the car was idling I took off the plastic shroud and sprayed all around the intake area and vacuum lines with wd-40 I heard no change in the engines idle speed. At this point I am lead to believe that it could be a map sensor, a tpc sensor, possibly a o2 sensor, hell maybe even a fuel injector. What has me baffled is that my ses light hasn't came on at all, and I know it works. Thus Frustrated!!! lol guess I am going to have to break down and take it to a GM dealer, my wallet aint going to like that!
 
Find someone local who gas a good OBDII scanner. You may have check engine codes. The SES light doesn't always come on.
 


Hold up a second. We are going to need more from you to help you.

You said LE, I'm not familiar with the LE. Yet you posted in the GTP section. Help us out, which engine do you have?
You said top of the line plugs, name brand? If you say Bosch Platinum, we are going to have you change them.
You said you changed X Y and W. You didn't change the Ignition Control Module, right?
You also said the stomping on the pedal took 1.3 seconds to move the speedometer, does the engine downshift and give you power w/o the speedo responding or are you saying there is a delay between the stomp and getting power?
 
ya, I don't have one of those scanners yet! lol but it looks like that's what its coming down too! The thing idles smooth and for the most part runs as it should just seems like it just doesn't have the umph it once had. Seems like it takes more throttle to get it up a hill and that's when every once in a while the tach freaks out and the engine stumbles.
 
sorry billboost, I have a 2003 Grand Prix Limited Edition with the 3800 II supercharger, my bad. I put in 3 new coil packs, I put in iridum plugs and yes I believe they were bosch, I did not change the ignition control module, and I replaced the plug wires though I must admit I did not notice the brand name of them as I was told at O'reily's that they were the best they had. I also have changed the crankshaft position sensor and the catalytic converter.
 
To my knowledge there was never an LE in 2003 with a charger. I thought that crazy GT/GT1/GT2 crap started in 04. I've been wrong before. Either way..we know what we are working with now. Good ole charged motor.

Well Bosch iridiums aren't all that great either. Try to stick to NGK, Autolite or AC Delco plugs in the future. If you get mistires in about a month, it's the Bosch plugs. Bosch stuff breaks down in our waste spark system faster than any other brand I've come across.

Your ICM might be giving you a hard time. IIRC the RPM is passed through the ICM or derived by it and passed to the PCM or the PCM is reading the RPM based off the 18X and 3x signals. We'd want to see the schematic from crank sensor to icm to pcm to cluster to ensure we are on the right track. PCM typically doesn't fail this way though.
 
to be honest with you this is the first GM product I have ever owned and I am 49! I saw the car liked its looks and loved the way it drove and handled so I bought it. I have very little knowledge about the 3800 series supercharged engine. I couldn't even tell you what the difference between a GTP,GT,SE or Limited Edition is. I just know how the car should run and its not performing the way it should thus is why I joined this forum to get help and advice from fellow enthusiasts such as yourself
 


Right.. that's why we are going to help you fix this baby up and get it running on all cylinders.

BTW in the owners manual and a few other places it says Premium fuel only. Heed that.. use 91-94 only. chipped pistons result from lesser grades.
 
I will take your advice and will change out the plugs tomorrow for one of the other brands you named, this way I will be ahead of that problem. The problem I am currently having just doesn't seem to me that its a major deal, its something small I am missing but its obviously big enough to spoil the performance of the car yet not trigger the SES light.
 
I'd have to dig further at home, but here's something I happen to have laying around
ICm.jpg


Makes a guy wonder if that's the rpm being handed off to the pcm/dash.
 
I use the highest octane I can get in Oklahoma which is 92, my wallet hates it but the car loves it! That's the price you pay for having a grand prix I guess. I will change the plugs out tomorrow and then off to the GM dealership it goes. I am obviously out of my league for now.
 


ok, dumb question here? am I an idiot or is the top portion of the diagram you just sent me the plug that plugs into the base where my coil packs sit?
 
See I wasn't totally crazy about the limited edition! I went and viewed that link you passed on and it describes my Grand Prix right down to the logos on the floor mats. Though my seats will be changed up as I am currently having them recovered in all leather, I hate cloth seats!
 
Let's not rule out you being crazy yet..lol

Yes, that top pic is the connector of the ICM, which sits under and fires your coils. And apparently has something to do with RPM signal. I want to confrim that the dash gets it from the ICM and that the pcm doesn't derive it.
 
Is one of the issues here that in 2003 there wasn't a LE grand Prix? Lol
also make sure you have those metal heatshields off the boot of the plugs. They cause misfires, mine was misfiring like crazy and no ses light took forever to get up to speed once I stepped on the gas. Removed them and everything was good.
 
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