Thread: Acceleration noise

suspenion would be nice. one day. some spring blockers for the rear would be nice to for the track

whats when mine would pop, on take off. they never shook the dash tho...

but yes new mounts should help

I gonna cross my fingers and hope thats the problem.I'll post the results after I do the mounts. I keep telling myself that i'm done modding, but then i see something new and can't help myself, it's never ending.

Today i took off easy and felt a very small bump, not nearly as big as when i chirp the tires. when gas and braking it i can feel a small thump. my main concern is that its a tranny problem, is there anything in the tranny that could go wrong with it, that would make the bump noise while gasing and braking, other than it being mounts?

idk but when my mounts were bad thats how it would do. i dont really think its tranny related

Traction control on or off, it doesn't matter. it does it even if i were to hit the gas hard enough to make the car jump from 0-15 mph. if the mounts are wouldn't i hear it at other speeds? like if i make the car kick at say about 35mph, no noise.

no i only heard it at take off.

lol bio nice motto haha does the car feel like a new and power beast now with the pulley and pcm gmpunk?

Yeah theres a BIG difference in power, I plan to get it on a dyno just out of curiosity. I haven't got really got to launch it off the line like i'd like to. do to the thump noise i don't want to do anymore damage. i'm putting all new mounts in on tuesday so hopefully that will fix it. I did the speed limiter test i got it up to 119 late last night. I remember the first time it hit the limiter at 108 it scared the hell out of me, i wasn't expecting it to be set so low. Another thing i noticed after the pcm, on cold starts i get kind of a erratic idle going from 1000 to 1500 rpms, the idle is normal once i put it in gear or the car warms up.

erratic idle? have you scanned it? what are you LTFTs? might have a vacuum leak.

if i had a vacuum leak would it only have a bad idle on a cold engine in park, once in drive the idle is normal?

The idle will settle down, I had the same problem when I installed my Overkill. Here's the response from an email I sent to Will.
My question;
Will, I put 400 miles on the car since installing the PCM and during start up I get a rolling idle until the car warms up. Will this eventually go away, is this normal and will the car develop any problems from this condition.
Thanks.
His response;
The rolling idle is likely to go away as the PCM learns more. No issues will develop, however it may be caused by a dirty mass airflow sensor if you have a K&N installed on your vehicle. If so have this checked out and cleaned with electrical cleaner as needed.

So I had new engine mounts and poly dog bone bushings put in today, got the car back same exact thing, thump when taking off hard and while gas and braking it in gear. As for the erratic idle, I cleaned the MAF as KISSMYSS suggested, still no difference. I got the car home after all the mounts and was pretty pissed that the thump was still there. I kept my stock PCM and decided to put it back in and take overkill's out. Instantly the thump was gone no matter how I tried to recreate the noise, I couldn't. I guess I just got a bad one? I e-mailed will, so i'll see what he says.