Miss at low RPM's while driving.....? [Archive] - GrandAmGT.com Forum

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Green99GT
07-08-2006, 04:35 PM
Its a 99 Ga 3.4 with 76,000 miles. At least i think its a miss because it dosent rev up, sounds like its dieing. It happens right around when it wants to down shift because its under a load, say around 1400rpm. And then if you stand on it it will miss too as it goes faster. Plugs are AC delcos with around 20,000 miles on them, wires a MSD bought at the same time. Fuel filter's been changed. Just curious if anyone else has ran into this. Im going to check the trans fluid tonight on a friends lift to rule that out, dosent leak any fluids. Wouldnt think an O2 sensor would do that. Although im lucky to get 22 mpg with mixed highway and city driving. Also no SES or SVS lights are on. Thanks for any thoughts.

xxbackhillxx
07-08-2006, 04:39 PM
has nothing to do with the transmission. check and re-check the plugs, wires, and coil packs.

Green99GT
07-08-2006, 04:40 PM
Why you rule it out so fast? because it dosent rev-up?

xxbackhillxx
07-08-2006, 05:10 PM
bc misfires have nothing to do with transmissions

Green99GT
07-08-2006, 05:24 PM
I understand that, but any othe GA i have worked on when it misses it tells you what cyl. though the SES light, i have no light. It acts like it wanted to down shift but it cant for what ever reason and does its jerking thing

GTKnightRider
07-08-2006, 05:54 PM
I get the same issue with mine. when Im crusing at around 1500 to 2k rpm it feels like it misses. I just changed my wires (taylor) plugs (autolite plat). how would I chenck to see if im getting enough output with my stock coil packs?

Green99GT
07-08-2006, 10:30 PM
Well I got the car on a lift tonight and put about 3/4's of a quart of tranny fluid. I pulled out the front 3 plugs and they looked fine, didnt have the will to do the rear 3, if i pull them they are getting replaced. im thinking hot coil pack, so i might buy one, or all 3 and replace them, see what happens. Have you tired anything GTKnightrider?

GTKnightRider
07-10-2006, 01:18 PM
No I want to test my coil packs at school (U.T.I.) before spending the money on new ones. It can't be my pcm because it had a problem before and after my DHP. Can't be the plugs or wires I just upgraded them. Im curious, what if its the crank angle sensor. It has this problem when its cold or hot so it can't be any of the tempreture controlled sensors. I wish they would let us use the dyno so I could test it while its under load.

Green99GT
07-10-2006, 08:53 PM
I have the DRL kit i was wondering if it wasnt something from that. Havent go tto drive it much since the fluid check, but it wasnt that low.....IDK

GTKnightRider
07-11-2006, 11:19 PM
One of my instructors stated It may even be a vac***e leak that may cause a low rpm misfire. I'll have him check it out at the shop on sat.

Green99GT
07-12-2006, 08:06 AM
yea i was thinking that too, i spayed some carb cleaner around and couldnt fine anything, the few lines look good, and the lower intake gasket isnt leaking again, dosent say much for the others.....

iceman
07-12-2006, 09:14 AM
add dirty injectors to the lsit

Green99GT
07-12-2006, 09:55 AM
that was a thought too, i have a bad habbit of watching my low fuel light......i do run some clreaners though it now and again and never noticed anything

NorKoastal
07-12-2006, 08:07 PM
Crank position sensor might be getting shorted.. Under 3K the car uses this to smooth the idle... Your water pump might be leaking onto the 24X sensor... Take a peek behoid the right wheel well.. The misses should be less pronounced over 4K though..

lovestheh20
07-12-2006, 08:28 PM
i have this problem too. one time I had a too rich code thrown, and I am getting am OHMs test on the injectors next week. when I had a bad wire, the car threw a code every time it had a misfire episode so I knew it was an electrical problem. but this one is different. infact sometimes the car doesn't want to start unless I keep my foot on the gas a little bit.

Green99GT
07-13-2006, 04:19 AM
Thanks for the info, mine hasnt sent a code yet, i wish it would lol. I dont notice any leaks under the car, and the fluid has remained constant but ill take a look.