99 GT running rough in gear, smooth in neutral [Archive] - GrandAmGT.com Forum

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Lspilot82
11-27-2011, 12:12 PM
Hey guys I've recently been having a issue with my 99 Grand Am GT. It has been running rough when I 1st start it up, then it clears up a little. Now its running rough when I put it in gear but smooth in park and neutral. What could be the issue. Also I've noticed a considerable loss in power awhile go, well before this idle issue started. My oil is clean, and doesnt look like there is water in it, but the oil does have a burnt fuel kinda smell to it. Idk what the problem is. Any ideas? Thanks guys.

MAC the KNIFE
11-27-2011, 02:45 PM
hey neighbor, i'm in brandon/plant city.
when you say rough, i'm assuming you mean the transmission. the burnt fuel smell when you take the oil cap off is normal, no engine seals perfectly, and a tiny amount of exhaust leaks around the piston and into the oil pan (it's called blow-by). so don't worry about that. if the engine runs smooth in neutral and park, then it's probably a transmission problem.
what do you mean by "rough"? is it jerky? is it in all gears, even reverse? is it shifting smooth?
how many miles on it? ever had the transmission replaced or flushed?

the more you can tell us about it, it will help us understand and give you the right answers

psy7
11-27-2011, 02:57 PM
that sounds familiar cause mine used to do that but need more info

Lspilot82
11-27-2011, 03:46 PM
hey neighbor, i'm in brandon/plant city.
when you say rough, i'm assuming you mean the transmission. the burnt fuel smell when you take the oil cap off is normal, no engine seals perfectly, and a tiny amount of exhaust leaks around the piston and into the oil pan (it's called blow-by). so don't worry about that. if the engine runs smooth in neutral and park, then it's probably a transmission problem.
what do you mean by "rough"? is it jerky? is it in all gears, even reverse? is it shifting smooth?
how many miles on it? ever had the transmission replaced or flushed?

the more you can tell us about it, it will help us understand and give you the right answers

Well hey neighbor...lol. I dont think its the transmission, I recently had it flushed and fluid put in it and it hasnt gave me any issues.

When I mean rough, I mean the engine itself is running rough, like there is a mis or whatever. When i 1st start it up it runs rough then clears out sometimes within about 10-15 seconds. When I put the car in neutral it runs good and smooth. It kinda feels like its missing under load when I put it in gear. I've read online that it could be a idle air control valve or something, but I wanted to jump on here and see what you guys had to say.

psy7
11-27-2011, 03:56 PM
might want to check the cat cause mine had the same issue under load

Lspilot82
11-27-2011, 04:03 PM
might want to check the cat cause mine had the same issue under load

I will definitely do that...thanks.

psy7
11-27-2011, 04:58 PM
np if thats not it then u will want to do compression and leak down tests to check cylinders and piston rings

sleepyalero
11-28-2011, 12:54 AM
feul filter perhaps too?

chris_gt_74
11-28-2011, 09:30 PM
Mine does this as well. New pcv, wires, plugs, clean air filter, clean MAF, and fresh oil change no water no codes. I have not done any transmission servicing and my fuel filter is not very old but could possibly need changing. Also the throttle body has been cleaned. I feel a light stutter in idle in park or neutral. But it is more pronounced while in gear and sitting at a stand still. Seems to drive okay but I would like to figure it out myself because it use to run very smooth and almost silent. I have 90k on my car by the way.

Lspilot82
11-29-2011, 12:03 AM
Mine does this as well. New pcv, wires, plugs, clean air filter, clean MAF, and fresh oil change no water no codes. I have not done any transmission servicing and my fuel filter is not very old but could possibly need changing. Also the throttle body has been cleaned. I feel a light stutter in idle in park or neutral. But it is more pronounced while in gear and sitting at a stand still. Seems to drive okay but I would like to figure it out myself because it use to run very smooth and almost silent. I have 90k on my car by the way.

That is exactly what mine is doing. Tomorrow I'm going to clean the IAC valve and see if that helps.

chris_gt_74
11-30-2011, 06:55 PM
So what happens if the IAC is unplugged while the car is running with the a/c on? I cleaned mine but prior to even cleaning it I unplugged it to see if it affects the idle at all and it did nothing that I could tell. Shouldn't some kind of idle change occur when it is unplugged? Also I'm not sure of the part exactly but the hard plastic tube that goes to the pcv valve, the black soft rubber tube that loops under and connects to a sensor collapses when the car is running which I'm sure is not suppose to happen. But has anyone else noticed it squeezing shut from the vacuum?

MAC the KNIFE
11-30-2011, 07:30 PM
if you unplug the iac, the iac valve will just stay where it was and not open or close any more. if you unplugged it while the car was already warmed up, then you probably wouldn't notice any change. you know how the car will idle a bit faster while it is cold, then the idle drops when the engine gets warm... that's the iac closing a bit.

as for the vaccum hose, i can't think of the tube that you're talking about. but if it's squeezing shut, then maybe your iac valve was completely shut and your engine was trying to suck air out of the cranckcase and collapsed the tube.
vacuum lines aren't suppose to squeeze shut unless you've got it bent around something and pinched it off.

if the vacuum tube is only collapsing while the engine is running, try cracking open the throttle just a bit and see if that alleviates the squeezed vacuum tube. sounds like your iac is completely closed and the engine is starving for air when the throttle is closed.

chris_gt_74
11-30-2011, 09:15 PM
This is the part (http://www.oreillyauto.com/site/c/detail/BWD0/CP515.oap?year=2005&make=Pontiac&model=Grand%2BAm&vi=1431254&ck=Search_purge+valve+solenoid_1431254_666&keyword=purge+valve+solenoid). The hose I am talking about is like neoprane or something really soft. Anyway when the car is running it is collapsed.

psy7
12-01-2011, 12:01 PM
u have a leak somewhere or clogged hose

chris_gt_74
12-01-2011, 06:55 PM
I fixed the hose, it was just very wore out and would close up with the vacuum. But while attempting to clean my iac I think I damaged it so I picked up a new iac, throttle body gasket, and some 3/16 hose. I took my throttle body off and thoroughly cleaned it up and installed and the new iac. I also removed the wore out hose and replaced it with the stronger fuel hose. All seems fine now and the purge valve solenoid is getting it's air now like I'm assuming it was suppose to. Not sure what benefit will come of it but it's fixed. My idle is much smoother now too but I am still feeling the ever so slight idle "mis". I will ad though it is barely noticeable. The rpm gauge shows a fairly steady 600-700 rpm.

psy7
12-01-2011, 07:43 PM
thats good just keep up with the cat and all sensors that can be bad if they arent working found that out the hard way

chris_gt_74
12-01-2011, 08:17 PM
thats good just keep up with the cat and all sensors that can be bad if they arent working found that out the hard way

Well whatever my slight mis is coming from it's not throwing codes. But I would love to track it down and get the smoothness back.

psy7
12-01-2011, 08:23 PM
u could do a compression test to see if rings or valves could be causing it

chris_gt_74
12-01-2011, 09:08 PM
Never done one. I'll have to check that out after the holidays. It's mainly just annoying and not so much a performance problem. I mean the car drives good and strong. I'm just missing the smoothness it use to have.

01GrandAmGt75annv.
12-01-2011, 10:46 PM
This is the part (http://www.oreillyauto.com/site/c/detail/BWD0/CP515.oap?year=2005&make=Pontiac&model=Grand%2BAm&vi=1431254&ck=Search_purge+valve+solenoid_1431254_666&keyword=purge+valve+solenoid). The hose I am talking about is like neoprane or something really soft. Anyway when the car is running it is collapsed.

That looks like the Part I need, On my dash, there is a check engine light on, and I failed my emissions because of it. went by a friend had him clear out the check engine light, then a week later that damn check engine light came back on. Prior to this, the guy who I bought the car from said there is a part on the motor which will need to be changed and showed it to me and push the black vaccum line further on the Valve. then he gave me a autozone receipt. PO440 HVAC ?

When I was taking off the rear wheels on the car, I found another one of these in the trunk. Any guess you think guys?

one also problem. When I pull up to a gas station and leave the car run, the damn thing revs up and down non stop until i get back in the car and puts it into drive it goes away.. anyone know what it could be?

http://www.autozone.com/autozone/parts/Duralast-Canister-Purge-Valve/2001-Pontiac-Grand-Am/_/N-jflcaZ9ixsy?counter=0&itemIdentifier=195791_0_0_



Sorry If I'm confusing.. at times I don't make sense. lol

chris_gt_74
12-02-2011, 04:48 PM
That looks like the Part I need, On my dash, there is a check engine light on, and I failed my emissions because of it. went by a friend had him clear out the check engine light, then a week later that damn check engine light came back on. Prior to this, the guy who I bought the car from said there is a part on the motor which will need to be changed and showed it to me and push the black vaccum line further on the Valve. then he gave me a autozone receipt. PO440 HVAC ?

When I was taking off the rear wheels on the car, I found another one of these in the trunk. Any guess you think guys?

one also problem. When I pull up to a gas station and leave the car run, the damn thing revs up and down non stop until i get back in the car and puts it into drive it goes away.. anyone know what it could be?

http://www.autozone.com/autozone/parts/Duralast-Canister-Purge-Valve/2001-Pontiac-Grand-Am/_/N-jflcaZ9ixsy?counter=0&itemIdentifier=195791_0_0_



Sorry If I'm confusing.. at times I don't make sense. lol

The one I showed above is near the throttle body but there is another of similar type somewhere in the back though I do not know much about it. I questioned mine merely because of the bad hose on it. I wasn't getting a check engine light.

As for the revving, could be several things I'm sure. What are your rpm's normally and when it revs up and down?