93 Grand Am 3.3L engine idling high

[Nitram]

Hello from a newbie - great forum you have going here!

Anyway, my problem is with my 1993 Grand Am 3.3L with around 125k miles on it. My wife bottomed out the car pulling into a parking lot and ever since then the engine has been acting really strange. Now, I am usually pretty good with cars, but this one is stumping me. The engine vibrates excessively (prob need new lower engine mount as this is where it bottomed out) - and the engine idles too high. It also knocks slightly, but I think it's because of the vibration. The noise is definitely coming from the area near the crank pulley, but I really think it's just the lower motor mount knocking around like the bushing is torn. My big worry is the engine idling too high. The car will cruise at 30mph for a long time without hitting the gas and it kind of surges when it's doing this. It also has a hard time downshifting under accelleration. I have replaced the plugs, wires, & O2 sensor. The oil is clean and full. There are no trouble codes current or stored. I have cleaned the intake area by taking the intake hose off and spraying cleaner into the MAF area so I think (?) the MAF sensor
is clean. I also searched all over for vaccuum lines that might have come off, but I can't find anything wrong. Probably 10 different people have looked at this car, but nobody really seems to know what's going on. I have heard that the #1 bearing has had problems with this engine - I was thinking it could be bad enough after being jolted aroung to make the engine idle too high, but that really doesn't make sense to me. It seems like a vaccuum leak to me, but I just can't find it anywhere. I even tried my old mechanics trick of running the engine and spraying carb cleaner around the intake gasket to see if it was leaking. So, if anyone knows any common problem I've never heard of or can help me out on this in any way, I would really appreciate it.

A big time thank you goes out to anyone that can help me.

[graden]

OK I hate posting like this because stuff like this can realy add up fast trying different things .... but my first guess would be your
throtal pos sensor, then your crank pos sensor. Now because you dont have any check engine lights on this might be down rooted to a larger problem like the crank bearing has been thrown out and the engine comp is trying to compinsate for it. Go see a trusted mech if you have 1 because I dont want to peddel easy anwsers. Mabey better to get your engine mounts checked out first and elim that problem . But I know when i played with my throtal pos sensor one night i had it reving to almost 4500 rpm when I turned the key over <---------- scared the crap out of me :eek: . needless to say I neverd played with it again.

[graden]

Originally posted by graden
me :eek: . needless to say I neverd played with it again.
and I decided never"d" to try and type when im sleepy again:doh:

[4kQuad]

Vacumm leak is my guess. Try spraying the carb cleaner along other vac-lines. For it to start running that high, some thing has changed in air/fuel mixture. Air would be my guess.

I have bought Docotor's stephoscopes to find vac-leaks. They work real good. Just start the car and put the end the Doc puts on your chest over the car and listen for a sucking sound, like a hole in a straw. They sell them at Medical stores for 10 to well over 100 dollers. I buy the 10 doller ones. Doc's listen for creeks and poping sounds in our bodys, they also find problems on cars.

It might be a waist of 10 bucks, but it might find it. I just like listening to the inside of the motor and such with them. If your a curios sort of person, the 10 bucks might be worth it to you.

You can hear top end, bottom end and water moving through the hoses.

Good luck.

[92CamaroRS]

i doubt its a vac leak as there really isnt a whole lot of vacume lines on this engine. id say check the MAF Sensor.

[mikem220153]

Just a guess, but have you checked the idle air controller (IAC) and it's passages on the throttle body? If it is clogged, it could cause a high idle problem. This is a fairly common problem on the 3100.

[92CamaroRS]

dont believe that the 3300 has an IAC

[mikem220153]

Yes, It does have an IAC.

[92CamaroRS]

you sure? didnt think they had it. huh oh well. i prefer an idler screw personally. you can change the idle

[mikem220153]

Yup, positive. I worked on one this weekend.

[Nitram]

Thanks for the replies, guys.
I have checked the MAF - I cleaned it really well and then I tried unplugging it while the car was running. Well, the check engine light came on with it unplugged like I figured, but no codes still when it's plugged in.
I'm really starting to think it's an inner engine problem. I don't know exactly what's wrong, but it definitely knocks (intermittently) and I've heard enough engines to know that it's not looking good. I honestly don't want to rebuild this thing so I'm probably gonna just trade it in for a new one. I guess I was just hoping that there was some other common or obvious problem that someone would point out.
Oh, and I tried the stethescope thing (I bought a mechanics one) and it's an awesome tool, but I couldn't find anything with it.
Anyway, thanks a million for your help - if anyone has any more ideas on it I would sure appreciate them cause it'll still be another couple of months before I trade it (if I can't fix it).

[JerryB]

Hey, I had the same problem it was the MAF no matter how much you clean them sometimes they just go... if its ever idling high again park the car and go and unplug the MAF. if the rpms drop its the MAF. damn mechanic replaced my IAC first thinking it was that but it wasn't .. I know exactly what you mean my 92 went about 35 without touching the gas

[Back In 92]

I have/had the same problem on my '92 3300, i havent started it since ive done all the work to it because i was replacing valves, lifters and head gaskets. But as i was taking apart the engine i found that a vaccuum part was cracked. I replaced the IAC but like i said i havent started the engine since replacing everything, ill let you know when i start it up though.