View Full Version : Grand am RPM's ticking up while accelerating
03-13-2012, 08:43 PM
I have a 1999 grand am GT and just a few days ago my car started hesitating while accelerating quite a bit... If i watch the RPM's they will almost tick up like a clock... It accelerates then stops and so on.... Also noticed when i started from a light i got on it a little bit and right when i was about to shift at about 5000 RPM's i herd like what sounded a pop hitting under my car... I dont know if i would explain it as a backfire or what exactly, but it sounded awful. Its done it twice now that i have herd.. The transmission does shift kinda hard just an FYI.... I did recently have intake manifold gaskets replaced as just a little more info to give... It has 74,000 miles on it now...
I was suspecting either a transmission going bad, or injectors?
03-13-2012, 09:19 PM
nice ride bro where at in Ohio are you? i live around cleveland. i dont know what county 48? is. btw you should get a red plate cover for the front and pop that plate in the dash!
but back to topic, did you attempt to replace the intake gaskets yourself or take it to a shop? its possible that something was... put together incorrectly. if you had no issues before, and now you do.. its a possibility. if it hesitates while accelerating it could be plugs/coil packs. does it bog down at all? and that pop what exactly does it sound like if you can describe it? like something popping out of place? like a metallic pop? it would be strange for a tranny going bad at 74k tho, especially on the 99's. from what iv heard the 99's had the best trannys in them. mine has 188k on it and just recently has it started slipping. but then again i drive it hard lol
03-14-2012, 08:00 AM
Hey thanks man! I'm from Toledo... Lucas county.... haha yeah I put a ton of work into this car as you can see... but no I did not do the intake gaskets myself... I went to autozone to talk with them and they recommended a Guy who comes to your house and does it, you just buy parts... but it ran fine after and that was done before winter... the weird sound I herd was right before it shifted at 5000 rpms when I was testing my giddy up at the light(; haha sounded like a aluminum can went up under my car... so I guess metallicy ... I went to autozone and ran It by them, and they thought it was tranny flairing? Or my computer thought my engine was going to red line so it was throttling back... eventhough I don't get that close to it.. I do have a cold air intake setup so my rpms do run a bit higher, but the sound it gives is amazing.... haha I would like to get this fixed, then get a tune to eliminate the top speed and add a bit more horse power then maybe redo exhaust... ohh also I guess it could be a fuel injector... they are nitorious to go bad on them..
03-14-2012, 08:02 AM
Ohh that's a bit old pic now, but I have halogen lights now which really make it look good at night
03-14-2012, 02:48 PM
Any suggestions? ?
03-14-2012, 02:56 PM
How long has it been since that guy replaced the gaskets until this problem started? My first thought would be maybe he messed something up on purpose so you'd have to get it fixed again. My second thought is you should have taken it to a reputable shop. Not that a shop might not sabotage something either (I've heard of it happening many times), but at least you know where to find them, and they should warranty their work. Anyway...
Just an fyi, your cold air intake has no affect on your rpm what-so-ever. The only thing that affects that is your right foot. ;) Oh yeah, and 99's did NOT have the best transmissions in them. GM made continual improvements to them right through 2005, and the last of the most significant durability changes where done in '03, so a 4T45E from '03 or later would be the best.
As for what the problem might be, it's hard to say without more info. Have you had the PCM scanned for trouble codes? It almost sounds like it could be an intermittent misfire that gets worse under load, and could cause a backfire at high rpm. It could be plugs or coils, or it could be a clogged cat. Could even be low fuel pressure/supply. When was the last time the fuel filter was changed?
03-14-2012, 08:54 PM
I thought the cold air adds more horse power which means my tannys going to have extra load and take longer to shift? :p may be a dumb idea but was just a thought hahahah... the guy did it during fall... so about 4-5 months ago? and i have never had my fuel filter changed... i cleaned my MAF today and it did run a bit better, but theres still a little hesitation WOT or after ive been driving it a bit.... noticed today my temp was about 3-4 notches past 200, straight up and down, and it rarely ever gets that high... but that weird sound i get is right when its about to shift at about 5000 PRMs WOT .... i got it about 115 today.... and didnt sound like it use to meaning not as good, but also another thought here, when the guy original did my gaskets, he forgot to plug in one of my spark plugs and one of the cylinders was misfiring so he tore it back apart and saw he forgot to plug it in.... I have no lights on on my dash so They said they couldnt see any codes that might give i away.... theres just so many things it could be.... I guess wouldnt hurt to take it for a diagnostic at belle tire since i get them for free there....
03-15-2012, 03:57 PM
First thing I would do is change the fuel filter. It should be changed about every 30k miles. I doubt that will solve whatever is making that noise, but it might make it run better.
03-27-2012, 08:03 PM
I had the same problem man. I changed my fuel filter and nothing. Changed my fpr and nothing. Changed my plugs and wires and it took the problem away and feels like I'm driving a new car again. Definintly start with the plugs and wires and the try your filter.
03-27-2012, 08:07 PM
Sorry I was just talking about the hesitation problem. As far as the poping noise it could be a variety of things. For now just don't drive the car to where it makes that noise again.
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