Hi guys I know this isn't a fbody, (I am a member of this site because of my Fbody) but I can't get anyone to help from a pontiac site, so I know grand am are similar sometimes to firebirds so here goes I have a starting issue where sometimes when starting the car it will crank and when you let off the key it seems to diesel or chug a little bit before either catching and running fine or stalling, i have changed the plugs, wires, air filter, fuel filter, emission lines,(the emisson lines not changed for this reason but cpu was throwing a code). Now, I'm under the understanding that it can't be a coil because the coil is either good or bad, it doesn't just kinda work,, it does or doesn't...... Is this right???? And I don't think it anything with the starter or flywheel because when it does fire up it works just fine, my only other concern is the timing chain, when is the recommeded change, how hard is it, and could this problem be caused by slack in the chain over time? Thanks to any who can help. By the way its 99 grand am v6 high output 3.4L, with 130000 miles on it. I noticed the other day (its my wifes car) that it has a noticable miss when idling say at a drive through, so help please...

 

crack a plug putting them in? wires touching each other or other metal and arcing?

 

maybe even take the intake off and clean the carbon out of the throttle body or have a professional use a machine to clean all the carbon out of your intake/heads. BTW if you clean the throttle body just open it with boot off spray in carb cleaner until all the black comes off the backside of the throttle blades then wipe the excess and put boot back on. youll have a hard time starting it right after but itll start and once it does run it outside a lot of carbon will blow out the exhaust.

 

Cool i actually bought some throttle body cleaner to do this the other day but haven't yet just wondered if there was something that had potential to harm the engine such as the tming chain or something but still yet with whole coil thing anybody know if a coil can be good on/off or if its bad it won't work?

 

not sure about the coil thing but i havent seen any newer grand ams such as yours have a bad coil. most likely its not the timing chain those are once in a blue moon theyll break but its fine dont worry about it. the throttle body cleaner will be fine.

 

what brand of plugs?? i hope thay are not boushs lol

 

um i think there either bosch +2 or autolite copper dudes

 

The 3400 hates the +2 or +4 type of plugs. Standard platinum tipped plugs work fine. I've never heard of a timing chain going bad on a 3400, you do understand its a single cam, center of V cam, right? Just like a SBC. Extremely unlikely you'll ever encounter trouble there. Also unlikely to be the ignition, especially if you've gone over the key compenents.

Now, the 3400 has a couple spots it can develop vacuum leaks, especially at almost 10 years old when rubber starts to get hard and crack. I would check every vacuum line for leaks, unmetered air going into the motor will cause all sorts of problems, and they will be most prevelant under idle. I've had the EGR valve stick open a crack and cause funky starting and idling. Also, a failing fuel pump can cause a host of problems one minute, and then operate fine the next. I'm curious as to what codes the PCM was throwing, that might be a big clue to whats actually going on.

Head over to grandamgt.com, there is a wealth of information you can find there. I used to about live on that site, I got into modding my 3400 in my 99 Grand Am, and have had it for over 150,000 miles, so I've seen a lot of different things with that particular drive train, and I have a comprehensive write-up in the performance section on the various modications out there for the 3400. I'll be happy to help if you wanna try and start working to narrow things down.

 

There really is no similarity to 3rd gens (maybe 4th gens).

If someone wants to PM you, that's fine, but this doesn't conform to thirdgen.org rules on tech forums.