GenVibe - Community for Pontiac Vibe Enthusiasts

zbyers wrote: ↑Wed Oct 30, 2019 3:18 am Welcome to the best group on the internet!

With your diesel noise, does it go away if you step on the clutch? or put the car into neutral? have you tried jacking up the front end (putting it on jack stands) and getting it "up to speed?" Having someone to listen around the vehicle while doing so is helpful.

Really nice picture by the way. Brownie points for posting one right off the bat!

You can earn a virtual high 5 by letting us know where you're located. You may be near someone who's willing to give you a hand diagnosing the noise.

joatmon wrote: ↑Wed Oct 30, 2019 1:30 pm If it is an engine issue, it seems that it should be possible to recreate the same RPMs and engine load in other gears, but if it truly only happens at 70 mph and under load, then I'd lean more toward a tranny/axle/wheel cause. But can't really say from here

If you do try jacking it up and running it up to 70 mph, might be a good idea to do it somewhere it won't be a disaster if falls off and suddenly starts moving at 70 mph

zbyers wrote: ↑Thu Oct 31, 2019 3:16 am i have a hard time thinking it would be anything to do with timing chain. I think you would have noise prevalent at the same RPM in other gear, or even at higher RPMs.

Is the check engine light on? It would be if it were timing related.

If it's not on, it would lead me to think it would be related to transmission/axle or some other noise.

Can you have a passenger take a video? Best bet would probably be upload it to youtube since I don't think you can post videos here.

tpollauf wrote: ↑Thu Oct 31, 2019 11:24 am Welcome to GenVibe. Awesome pic by the way ! I agree with the drivetrain, thought of possible issues. When heavily loaded (which is your potential problem) the engine is working it's A S S off. Jacking it up & running it will somewhat recreate the experience BUT with half or more of the fuel being consumed seeing how it would be a non-load test. Are you burning premium fuel like these GT's are suppose to drink? It could be spark knock from low octane fuel and only noticeable when it's loaded very hard. Just a thought! Good luck

jolt wrote: ↑Mon Nov 04, 2019 10:39 am What brand of spark plug and coil packs did you use as replacements? If the parts are no OEM then I would change them. High speed miss under load could be caused by off brand parts like these. I have ran into this same problem more then once. It will act just like you disscribed, everything will be fine until under load at high speed. The electrical system in my 2009 Vibe is designed by Denso. Spark plugs and coil packs all say Denso on them......replace with Denso so weird things like this don't happen.

Is the intake air system all stock? From the air filter box to the throttle body? Stock style air filter? Have you cleaned the Mass Air Flow Sensor? These are things that can upset the air fuel balance and may led to a high speed engine load stumble too. I would start with the spark plugs if not Denso. I think NGK spark plugs were also used from the factory but sticking with Denso would be your safest bet.

NebraskaVibes wrote: ↑Tue Oct 29, 2019 5:08 pm After getting the car repaired once I'm up to 70mph the engine is pretty loud and almost sounds like a diesel at highway speeds. ........ When I am driving over 70mph and let up on the gas, the sound goes away.

tpollauf wrote: ↑Wed Nov 06, 2019 8:53 pm I doubt that it would be the throwout bearing as that is NOT a part that is subjected to varying loads. Basically it has ZERO pressure on it when the tranny is in any given gear, and when at final cruising speed, engaged in sixth gear, it is just sitting there doing nothing at roughly 3100 rpm, which you could achieve at any of the other five gear combinations at lower speeds. I hope I'm wrong for your sake so you can put this mystery to rest BUT I really doubt that is your problem

jolt wrote: ↑Thu Nov 07, 2019 1:30 am

NebraskaVibes wrote: ↑Tue Oct 29, 2019 5:08 pm After getting the car repaired once I'm up to 70mph the engine is pretty loud and almost sounds like a diesel at highway speeds. ........ When I am driving over 70mph and let up on the gas, the sound goes away.

Getting on and off the gas does not change the throw-out bearing load. Any noise from the throw-out bearing is going to stay the same. It is not the bearing if the noise is changing as you have stated above. The bearing load does change if you press the clutch pedal in or out but the gas pedal has no effect on the throw-out bearing loading...or noise from the bearing.

Your other statement that I have quoted above is that the noise started after you had your car repaired. You said they replaced the spark plugs and two coil packs. Did they replace anything else at that time? After they changed those items is when the high speed noise started? .... just making sure of this.

You may want to get a second opinion on this from another service garage because the pieces of this puzzle do not fit with the information provided. Does the "Check Engine" works when the key is just turned to the "On" position and the "Check Engine" light goes out when the engine is started? Stock factory exhaust system? Transmission lube changed?