Feels like it may die/buzzing (unrelated problems I hope)

[PCGUY112887]

Ok so first off, say i'm sitting in a drive through, sometimes it feels like the engine is giving off little misses, like you can feel/hear a bit of a "shake" from the engine when sitting there. RPM's don't really jump around, just sorta feels odd. It's probally totally normal, but I was wondering if it happened to you as well.

Something else about this, sometimes when say i'm pullin out and I have the wheel cocked hard and my foot on the brake and i'm sitting still, the car will sorta surge and almost die. It did die once in fact, pulling out of my driveway in reverse, turned wheel hit brakes, RPM's jumped down to about 500, then I shifted into D at practically the same time and killed it. I know wheels/brakes cause extra stress on the motor, but it seems like it's idle should hold strong?

And as far as the buzzing, it sounds like it may be comming from the tranny. Say i'm sitting there in line again, near a wall or something so you can hear it, you can sometimes (almost always) hear a buzzing... sounds like an electrical buzz but I have no shorts as far as I know of. If I put it into park then it stops for a second, then will start again, and sometimes just randomelly stop/start again without me doing anything. I don't beleive it does it if I go into reverse though, not sure about N.

Any thoughts? Thanks.

[PCGUY112887]

Oh cmon

[sharkey]

sounds like you have a vacume leak or need to clean the iac valve/passage. when you crank the wheels to the locks, the power steering will drag the motor down. when you step on the brakes, it will drag the motor down at idle due to the booster. usualy the ecm can correct the idle for this, however if the iac passage is clogged, or you have a vacume leak, the idle wont pick up fast enough and can cause it to stall.

as for the buzzing from the tranny, my only thought is pump or filter pickup noise. id check your tranny fluid and if its right, add another quart. its not gonna hurt to have the tranny overfull. if the noise goes away, id lean towards a bad fliter or filter seal. if not, could be the pump.

[PCGUY112887]

Where exactelly is the IAC? I've been wondering to check it but i'm not sure where to look heh.

And as far as the tranny, fluid and filter was swapped out a few months ago. I noticed that it would tend to fall out of gear in a hard left(?) turn so I overfilled some per instructions by some other members. Later on it started to shutter real bad when downshifting from OD to third under load so I put in some lucas... never seemed to do a whole lot it's not doing it as often now but it still happens.

I'm not sure what to think :-/, no SES light or anything when it shutters. I've noticed that sometimes when sitting still in drive that the engine will sputter, go down to about 400-500 rpm's, then go back. If I put the car in N or into P it doesn't do this. Could some TCC control be going out so it's not locking/unlocking correctly when downshifting? Someone suggested to me that maybe when i'm sitting there it starts to lock/unlock (whichever it shoulden't be when sititng idle lol) so the tranny starts to bring the engine down then it relocks/unlocks/whatever and it goes back up.