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2003 Grand Prix GT Engine Sputtering and Stalling

A

Antonio Giarratano

New member
Own a 2003 Grand Prix GT. Bought it used, great condition. Ran beautifully the first year or so, until recently when it has started puttering and stalling when stopped or idling and has been intermittently misfiring, and I don't know if it's related, but when I drive it and then turn it off, there is a lingering smell of coolant. Have taken it to a mechanic and had a few things done. He ran it and hooked it up to a computer, no irregular codes except for when it misfired.

Here is a list of things I have done/had done since this started:
Oil Change
New Spark Plugs and Wires
New Fuel Filter
New MAP sensor - ran decently for a few days afterward.
Water/Ethenol treatment - worried about water in the line/tank

Have been worried of something in my fuel or oil, which would point to a blown head gasket or something, but oil looks normal and the exhaust looks normal.Air filter looks like new. Will be attempting to replace Mass Air Flow Sensor, once I get the 100 or so dollars to buy one, but figured to post here to see if anyone has been having the same issue and has found a remedy or to get an idea of one because I am tired of bringing it to mechanics who will do work but do not fix it, I understand that sometimes, unless it is something that is right in your face, pinning symptoms to a problem can be a checklist of things, but one's pockets only go so deep.
 


I wouldnt replace parts that are not bad.

Do you by chance know which spark plugs you used when you changed them out???

Random stalling like you say its been doing is a tall tail sign of a crank sensor on its way out.
 
Um, instead of replacing the MAF, why not just try cleaning it??? A new MAF is $150+, while a can of cleaner is $7.

Also, since you smell coolant it would be a good idea to check your coolant elbows, hoses, etc... Are you loosing coolant at all? Could be time for LIM gaskets.

What type of plugs are in it currently? If they are platinum anything, get them out and get a set of copper plugs from NGK or Autolite in there (or the stock AC Delco Irridiums). These motors do NOT run on platinum plugs.

Then I would check for vacuum leaks.

You have to try really really hard to blow a head gasket on these motors. It's that rare. How many miles are on this 03?

You say there were codes from when it misfired. What was the code? This will indicate which cylinder to look at, or if it's a P0300 its a random misfire.
 
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