Major problems with my Grand Am GT (w/ 2.4 TwinCam)

[82-T/A]

Hey guys,

I have a 1997 Grand Am GT. The car runs like crap. It started doing this two weeks ago, and I really want to get this taken care of.

Here are my symptoms. When I first start the car, the car idles perfectly smooth. It'll continue to idle perfectly smooth also without any problems.

The car will accelerate normally so long as I do not give it any more than 1/4 throttle. If I give it like 1/2 throttle, the car will bog down severly.. almost to the point where it'll want to stall out. So much in fact that even when I let up off the gas, it's next to impossible to get the car to stop hesitating.

Just took it out for a spin tonight and I had the same symptoms. When I pulled it back in it's parking space, the car died. I started the car up (with many cranks) and it finally started, just barely... I tapped the gas a couple of times, and then it started to idle perfectly normal again.


When this first happened, I got a check engine light flash on and off. I bought an OBD-II scanner and it gave me a generic error saying "Multiple Cyl Missfires" and that's basically the extent of it. The car gives no other errors.

I also noticed that when I first started the car, I got out and smelled the exhuast, it smelled really rich. Like that one time I installed 19lb fuel injectors in my Fiero's engines instead of the 15lb injectors.


NOW, my questions are:


1 - If either of my Oxygen Sensors are bad, is it possible that they can fail without sending a signal?

2 - Can I test to see if the O2 sensor is bad by disconnecting it? Will the car still run (although very rich?)

3 - If it's my fuel pump, would it really act like this, or wouldn't it fail completely?

4 - Is there a way for me to check my fuel pressure? I've got a fuel pressure gauge, but I don't see a schrader valve anywhere on the fuel rail.

5 - Any other ideas what it could be?


I cleared that cyl misfire code, and there are no other error codes.


Any help is really appreciated. This car runs like crap, and I'm so tired of dealing with it. It ran flawlessly before then. I have new plugs in it, clean Redline Synthetic oil, the transmission filter and fluid were just changed 10k miles ago... the car is up on it's maintenance...



Thanks...

[GlisteningWhite]

My car is doing the same thing i tought it was my injectors, but it wasn't brought it to the dealership and they said it was my spark plug wires, so i bpught a new set and still, same ****, then i replave spark plugs nothing!!! I can't take it anymore i just drive it to work and back! If anyone else has this going on please let us know!!! Help!

[82-T/A]

Well, I guess it's good that I'm not the only one.

FYI, I just got through replacing the main oxygen sensor. I had a spare one which I knew was good (got it from my other 97 Grand Am that I used to have).

I also replaced the top IDI cover... the thing that the coil pack is built into that says "2.4 TWINCAM". I replaced that with a good one from my old car too.. same thing.

So I've ruled out the main O2 sensor, and the ignition coils.

I'm totally confused...

I know there's one more O2 sensor behind the catalytic converter, but I don't still have the old spare one.

Any ideas guys??

[Metallman56]

it could be 2 things. i put bosch quad platnum in my grand am and multiple cylinder misfire came up with my scaner, i put ac delco back in light went off car runs fine. if its not plugs or a fuel problem which you have ruled out what about a air problem. like the mass airflow senser. it sounds like its starving for something and if it aint fuel or spark theres only one other thing it could be. air. look at the wires right by the top of the throttle body make sure there all ok, and hell even check you air filter. that cant hurt anyrhing.
hope it helps

[82-T/A]

Originally Posted by Metallman56

it could be 2 things. i put bosch quad platnum in my grand am and multiple cylinder misfire came up with my scaner, i put ac delco back in light went off car runs fine. if its not plugs or a fuel problem which you have ruled out what about a air problem. like the mass airflow senser. it sounds like its starving for something and if it aint fuel or spark theres only one other thing it could be. air. look at the wires right by the top of the throttle body make sure there all ok, and hell even check you air filter. that cant hurt anyrhing.
hope it helps

Well, you make an interesting point.

But, I don't think my 2.4 TwinCam has a MAF sensor. I don't see one anywhere in the intake.

However, someone mentioned to me on another board that it could be my MAP sensor...

I didn't even know the car HAD a MAP sensor.. but I think maybe it's that little itty bitty thing. I'm used to seeing MAP sensors from the 80s which are huge...

I'm going to see if I can find the spare one I had from my old car and swap it out!

Thanks!

[DevilSlayer]

What plugs did you put in? Like Metallman56 said, and is a well known fact here, that bosch plats cause multiple misfires. Go get some AC Delco's and put those in and see how it runs.

[82-T/A]

Originally Posted by DevilSlayer

What plugs did you put in? Like Metallman56 said, and is a well known fact here, that bosch plats cause multiple misfires. Go get some AC Delco's and put those in and see how it runs.

I have original stock steel tipped AC DELCO plugs in there... I changed them out around 68 thousand miles. The car has 88 thousand miles and I recently bought 4 new AC DELCO plugs that I was planning on installing when I got the chance.

Someone suggested to me that it might be the MAP sensor... what do you guys think?

It does seem to perform similar to how my V6 Fiero did a long time ago when the MAP sensor failed. I guess the only difference was that the Fiero had a V6 so, like GlisteningWhite's V6 Grand Am (above), it had enough power to allow you to continue driving, but just not with any real acceleration.

Have you changed the ignition cables(spark plug wires) recently?

[action]

The 2.4l dont have plug wires, it has those little caps becuse the coils are on the engine cover which he already replaced with no change.

[82-T/A]

Well, the MAP sensor didn't do the trick.

I'm bummed...


Because I have a spare engine (and whatnot), I think I'll try swapping out the TPS and the Fuel Pressure Regulator.

They're both pretty easy to get at, and it won't cost me anything except maybe an hour of work in my driveway....


If that doesn't fix the problem, then my guess is the fuel pump, maybe....

[Metallman56]

probley not the fuel pump, those tend to just die not act up. however there is some sort of screen on the fuel pump in the tank that could be clogged from perhapes rust in the tank. also if i remember right there are like 3 things that plug into the side of your throttle body check all of those. also perhapes theres something wrong with the throttle body opening up. take the airbox thing off and have a friend press the gas and see how open the throttle body opens up,but dont turn the car on. if all of this doesnt work i have one more suggestion. . . buy a new car or engine. good luck dude hope it helps

[82-T/A]

Originally Posted by Metallman56

probley not the fuel pump, those tend to just die not act up. however there is some sort of screen on the fuel pump in the tank that could be clogged from perhapes rust in the tank. also if i remember right there are like 3 things that plug into the side of your throttle body check all of those. also perhapes theres something wrong with the throttle body opening up. take the airbox thing off and have a friend press the gas and see how open the throttle body opens up,but dont turn the car on. if all of this doesnt work i have one more suggestion. . . buy a new car or engine. good luck dude hope it helps

Yeah, I know... tell me about it. I've got a Solstice on order... but I won't get that for another 2 months...

I love driving the Vic, but it's massive and sucks gas...


Thanks... I'm going to swap some parts out today and see what I can get it to do...

[Undersexed]

I had that problem one time on my old saturn and it was a coolant temp sensor... it was reading way too cold and was telling the car to dump fuel to the engine or something, but it came up on diagnostics(dealership of course)...

[Metallman56]

any luck?

[82-T/A]

No, I still haven't fixed it yet. It's not my primary vehicle so it's just sitting there right now. I'm SOOOO f**king ****ed at this car.

I'm guessing it's the fuel pressure regulator. If it's not that, then I just have no clue what it could possibly be.

I just cannot understand how a car with 88k miles could have SOOO many problems with it. My other 97 GrandAm went to 117k with no problems.

If the FPR doesn't fix this, I think I'm just going to donate the car.

The computer gives me absolutely no codes except "Multiple Misfires Detected!"

[Metallman56]

hey i just thought of something. try valvaline syn fuel injecter cleaner. its like $7 but it could clean all the crap out of your fuel system. its worth a shot!

[82-T/A]

Originally Posted by Metallman56

hey i just thought of something. try valvaline syn fuel injecter cleaner. its like $7 but it could clean all the crap out of your fuel system. its worth a shot!

Well, I don't think that's my problem. About 6 months ago, I already used the BG Chemical Cleaner fuel injector cleaner. I use it on all my cars every 30k miles.

[Metallman56]

any luck?

[O1GAGT]

Check the fuel pressure at the rail, how old is the fuel filter?

Check the throttle position sensor voltages, if your sensor is bad this could cause what you are expierencing.


Also check the coolant temp sensor

It honestly doesn't sound like the Fuel Pressure Regulator to me

[82-T/A]

Thanks guys,

I'm going to try to fix it this weekend, I've just been really busy with cleaning up the mess this hurricane left.

I'll let you guys know...

thanks for the advice.