Help. Engine/Transmission Problems

[Brass_GA]

My 2001 Grand Am has some serious issues that I really need some help solving. It's the 3400 engine with automatic tranny.

Problem:
Severe studder when accelerating
Surging when holding speed at 80km/hr @ 2000rpms
Rough Idle

The studder seems to occur the most after the engine is warm and only when shifting from 1st to 2nd gear. The harder/faster I accelerate the worse the studder. It kinda feels/sounds like the transmission is unable to find the right shift point or is just plain slipping. The fluid and filter were changed about 15,000kms ago. I've read that the torque converter can cause this and that the car does not use the TC when driving in 3rd. My problem occurs in both drive and 3rd gear.

So far I've cleaned the throttle body and the IAC and it calmed my rough idle a bit and increased pedal response but the rough shift and surging is still a problem.

I'd be very happy with any and all help anyone can provide.

[xeroinfinity]

Welcome to Af Brass GA !

HAve you had the trany scanned for codes?
Most trans codes dont trip the SES or SVS.

The simptoms you are describing sounds like a CV joint issue. Lets Hope
On the surge check and make sure all the vacum lines are connected, and none are cracked(like the thin gray hard lines on top of the TB). Make sure your pcv is working.

[Brass_GA]

No. I haven't taken it in to have the transmission scanned. I'm going to see about getting it in soon.

I did notice something odd when cleaning the IAC and TB. There is a bracket that mounts to the top of the TB that supports the yolk and cables for the throttle plate. There is a line that runs underneath it that continues to the PCV. Off of that line directly under the bracket is another connection. If I remember correctly it enters the engine just after the TB. It was quite loose, to the point where it looked like air could be brought into the line from the engine bay. I don't know what that device is but it seems to me that it shouldn't be loose.

[xeroinfinity]

Yes it gets loose another fine engineered part.

They arent supposed to leak but it will and it will affect the performace of your motor just like a vacum leak.

It connects to the O2 device under the ciol packs. Thiers also another vent on the back valve cover that connects up front to the manifold(i think) by the fuel pressure regulator.

You can take the part under the TB off and pull off the rubber sealthats loose, and goto a parts store and find a replacment if you need. The rear one(on the rear valve cover) is the same size and shape.

also, sometimes a shudder is the trans though and its not good
But you can check those CV joints by jacking up the car and checking them out.
Make sure the boots are in good shape and not throwing grease everywhere , thats messy.
Might hav the trany fluid checked too, maybe a little low and causing some shudder/vibrations.

But your best bet is getting it scanned, then go from thier.

[troy1]

get it scanned look for a p1811 a bad pcs can cause a launch shudder.

[BNaylor]

Just a suggestion in addition to the good advice above but check into the possibility of a flaky intake air temperature sensor (IAT) and/or the electrical connector to it. A flaky IAT sensor will make the tranny look bad such vibration, shudder, poor upshifts and going into reverse.

Normally it throws an odb-ii error code and SES light but not always. It has been a common problem with Grand Ams and Aleros with the 3.4L V6 and 4T45E tranny.

[xeroinfinity]

Good advice Bob, totall forgot about the IAT

Guess one cant always think of everything

[BNaylor]

Originally Posted by xeroinfinity

Good advice Bob, totall forgot about the IAT

Guess one cant always think of everything

No problem Xero. Keep up the good work.

It was fresh in my mind since we just had two similar issues over at the Alero forum. Plus some Grand Am owner PM'd me yesterday inquiring about IAT and tranny issues.

[Brass_GA]

Thanks to all of you. I should at least be able to check into the IAT myself. Any idea what a new one should cost me?

[BNaylor]

Originally Posted by Brass_GA

Thanks to all of you. I should at least be able to check into the IAT myself. Any idea what a new one should cost me?

Aftermarket around $10. GM AC Delco $18.96 list price, PN: 12160244.

Checkout these two posts and see if your symptoms are similar.

http://www.automotiveforums.com/vbul...d.php?t=600280

http://www.automotiveforums.com/vbul...d.php?t=605788

Good luck.

[xeroinfinity]

Originally Posted by bnaylor

No problem Xero. Keep up the good work.

It was fresh in my mind since we just had two similar issues over at the Alero forum. Plus some Grand Am owner PM'd me yesterday inquiring about IAT and tranny issues.

Thankx I'll try

I have heard of folks pulling the MAF off and spraying TB cleaner in while its running
thats not good ! kills the IAT about everytime.

[Brass_GA]

Well that would be my fault for following the directions on the TB cleaner...
Although the problems I'm having started long before my "cleaning"
I wouldn't be surprised if I have a vaccum leak somewhere. Unfortunately that would seem to be a tough thing to find.

[xeroinfinity]

Hey Brass_GA,
vacum leaks can only happen on vacum lines,
does that simplify the search
haha Just Kidding!

Most of the time you can hear the "hiss" of the leak if you listen close.
If you hav a long tube(or pipe) just follow the lines while listening and it'll help pick up the sound(s).

[Brass_GA]

Well it's show and tell time guys. I'll show you some pics and you can tell me what you think

I was doing some investigating tonight when I spotted what I think to be a possible vacum leak. I noticed what looked like carbon deposits on this line and I'm pretty sure I could hear a hissing that got louder as I increased the throttle.

PIC 1 - Main concern. Looks like a leak to me. Not sure what the line is for.
http://i90.photobucket.com/albums/k2...A/DSCF1888.jpg

PIC 2 - Lower view.
http://i90.photobucket.com/albums/k2...A/DSCF1887.jpg

PIC 3 - Unknown Port. Looks like a line should be connected here. Maybe for a different engine config?
http://i90.photobucket.com/albums/k2...A/DSCF1890.jpg

Let me know what you think. Is there a safe way to test this for leakage?

TIA.

[xeroinfinity]

the pics, the metal tube running down that has blackish stuff on it would be your power steering hose, not a vacum, and its getting a small leak started.

Not bad enough to cause concerns at the moment.

that port on the back of the intake isnt used and should be caped like it is.

Most of your vacum lines are on the left side(drivers).