firehawk68mcleod

iTrader: (2)

hey everyone i have a question... i have a problem with my trans am. when im on the decell.. say im going bout 35 mph and im slowin down, and the car is running on it on power close to an idle. the rpms will drop below 500 rpms and come back up. some times it even dies completely. My car is a auto. my first thought was a vacume leak. so i replace intake gaskets and replaced all pcv tubes .. with no luck.. the pcv tubes seemed to help for the first test drive but fell on its face. And another thing i have noticed my car idles way below what other ls1s run.. when in park it will set about 600rpms and when in drive its sit close to 4. If anyone can help me, it would be appriciated, thanks.

WarmWeatherBird

Is your battery gauge doing anything odd?
I had my alternator checked 3 times because I had a similar problem - It didn't die with deceleration in general - but death could come when I'd stop at a light or pull up to park... I'd have to keep revving the engine to keep the RPMs up high enough to keep us moving. Although if it was night and had all my accessories (lights, etc) running I would get some serious hesitation at lower RPMs. My battery gauge would wobble around. So had the alternator, battery and starter tested 3 times (done free at many auto part stores), checked to see if belts were loose/slipping, asked everyone I could find if they'd seen anything like it. All tested fine.

Of all the things it could be - finally resolved it when a gent suggested that many power problems come from bad ground. I'd added a single sub and amp to the car and tied its power to my alt battery connection. My ground bolts all looked clean, but one ground over on that side had a small amount of the finest white dust in the general area. Took off the bolts - wirebrushed them nicely - battery gauge settled back in to pretty much normal, rpms seemed normal and hesitation gone. Knock wood - I've had no more problems since and it's been a couple weeks. I plan on brushing every ground I can find under there when the weekend rolls around - HA! I also bought a heavier cable to run from my ground to the frame.

Don't know if it could help your situation - but I sure was pleased to find mine was such a simple fix.
Good Luck!!

firehawk68mcleod

iTrader: (2)

i mean its always sat at a little under 14amps but thats bc i had a copasitor for my stereo. but its always ran fine before just recently has it started acting up. i also have a optima battery.

WarmWeatherBird

Pre-problem, mine had always sat right on the middle mark at 13. Maybe slightly over. And it never seemed to budge. I had the titanium or gold model battery sold by Advance Auto Parts. I don't know what an optima battery is but I assume it's good stuff. I didn't add a capacitor to mine because the guys at the stereo store told me my little 10" sub & 2 channel amp wasn't going to draw enough power to cause me to need one. I go from a 4 gauge at the alt battery connection down to a distribution block - split off to an 8 gauge to the amp. (Trying to decide what to do about my monsoon amp - so I've got it set up so I can add another one out of that distribution block without rewiring anything if I decide to switch it out)

Before the ground suggestion, I had my battery switched out thinking maybe it was bad - the folks there were very nice. Gave me a free switch since it was still it was still in the free replacement window. (just under 2 years since purchase I think?) I figured it couldn't hurt - I've had firebirds since '94 and my experience is that the battery either works or doesn't. These big V8s seem to draw a lot of power on crank. I never get that warning weak crank. I just come out and the thing doesn't work anymore.

When trying to troubleshoot - I told everyone about the sub add - but no one seemed to think it would pull enough power to make a difference and explain my hesitation/stalling problem. But it was the only thing I'd done to the car recently. I checked my remote turn on wires - all were good. So I wasn't leaving the amp on after turning the car off. The tests showed almost zero drain on the battery. So was still scratching my head. (and revving my engine)

I figured I'd tried the other stuff - even had the tests run at different store locations and then compared the charts and numbers. All were consistent and indicated a healthy car. The stores said those parts had a clean bill of health. But my battery gauge was still wobbling around and I was still having the problem at idle. When it would wobble down towards the yellow was when I'd start having problems. I wondered if maybe I'd just hit the point of needing a larger alternator. Or if mine was on its way out.

When the gent recommended looking at my grounds, I double checked the ground on my amp and anchored it down with a bigger screw. Then I unhooked the ground bolt on the driver side near the alt battery connection and scrubbed it with a wirebrush until it was shiny. It looked a little tarnished - but I wouldn't have thought that was considered corrosion. Shows what I knew! Put it back together - battery gauge settled down almost completely. No more hesitation. No more low rpm idle.

After the gent suggested a ground problem, I skimmed through a couple articles online that talked about grounding issues. Please double check my homework because I'm probably not explaining it right - but basically the way I understood it was if you hook the power up - and it can't find a suitable/comparable ground to exit - then it will go back up the way it came in looking for an exit and cause a problem. Maybe check the ground on your amps/system to see if they're arcing against anything else or have vibrated loose? And that ground under the hood was instrumental in fixing my problem. I read about some people adding ground straps to their cars for extra ground. But when I checked at the auto parts stores, the only thing they showed in the part inventory was an ignition ground - and it was a factory item. I just wanted to add more routes to ground for my car. So I bought about a 40" battery type cable that I can connect from my main ground to the frame. Haven't installed it yet, though.

I don't know if it could be what's wrong with yours, but it's easy enough to do/check. At least if it didn't work you could rule it out and move onto checking other parts of the system.

firehawk68mcleod

iTrader: (2)

still having issues with idle and then engine still stalls.. anyone have any other ideas

J.C.

iTrader: (1)

I'm having the same problem here. Sometimes it starts ok and runs ok but other times the needle starts flickering. It'll keep turning of at idle. I have to give it gas so the needle can stay above the yellow mark. Not sure where all the grounds I should be checking are located.

LS6427

iTrader: (2)

Firehawk...JC.....

Sometimes when a fuel filter is getting clogged up your idle is affected. When you're on the gas the pressure builds up and usually can overcome the dirty filter to supply enough fuel pressure.

Its an easy cheap thing to weed out.........about $12.00 and 5 minutes.

.

HotSilverBird

You need to have the pcm scanned while its running to check what is really going on. Could be a vacuum leak or some thing electrical. You need to see what rpm the computer is setting at idle and the actual rpm. Sounds to me you have a IAC motor problem or something electrical. Even if you had a vacuum leak the computer should raise the idle to compensate.

lt1pwr1

iTrader: (1)

Before you throw money into parts at the car, take some carb cleaner and clean the throttle body and throttle body blades really good. You can get carbon buildup and it won't let air past the blades. If that doesn't work, you really do need to get it scanned. It could be a ton of things (IAC, bad o2's, etc.).

Without reading live data, you will be playing a guessing game. When it is running, you could also try tapping on the IAC lightly to see if the idle picks up. It could even be the plunger on the IAC that has carbon on it and isn't letting air go bye. You can try cleaning that as well. Those are virtually free ways of trying to solve your problem before you take it to a shop.

J.C.

iTrader: (1)

I don't have to turn my car on for the battery needle to start going up and down. I put the key in just to where the electrical turns on and that's where I can tell I'm already having problems. Needle flickers then settles down. Sometimes it starts right away and stays on and sometimes it starts but then the battery indicator goes to yellow and turns off.

LSX Performance

Bump...

Did you resolve the issue?

Im having the same issue, but not all the time. My car mostly does it when the ac or rear defroster is on. Any ideas?

firehawk68mcleod

iTrader: (2)

No, i threw a rod, two months later lol

Jorgens

Funny thing. Mine did something similiar this morning. cranked over but wouldn't stay running. cranked again and kept foot on throttle and was ok, but would dip down to 400 rpm when off throttle. took about 5 seconds to works back up to 1k. 4 months ago I fired it up and idle spiked to about 1800. I call it voodoo. After an hour of just letting it sit and ponder on it, it fired up normal. I came across this thread in a search for idle problems. I was thinking tb position sensor or something similiar and or fuel filter. However, I also thought i heard a faint tick which i never noticed before... Not sure what the problems is and or if anyone else is have a similar problem....

85CamaroZ28

iTrader: (7)

Mcleod and I had a long discussion about this a while back. Check wires going in front of the battery tray to the ECM and follow them around. Those are for the MAF, O2's all that good stuff. It really is most likely a ground. I went back and forth on this and after doing my intake manifold (replacing all gaskets), tb (new sensors and cleaning), Headers (gaskets and o2's) and changing the MAF twice, and finally tuning it and it STILL had a low idle. I finally said fine it's a ground and started cleaning off every one I could get to. I think I found five or six that needed to be cleaned. I used some thread chasers to clean out the ones on the radiator support and just went to town. It idles much better. No more surging when I come to a stop.