Basically, when the car is in neutral (5-speed) at idle, the car vibrates. The rpms are 800-1000. But, if you push in the clutch and put into 1st gear, there is no vibration. What is this most likely?
Well when I bought the car it had 155,000 on it now I've put only a couple thousand more on it....mostly aggresive driving. The clutch has always been pretty stiff so I've thought it's an aftermarket clutch but it could very easily be the stocker. The rpms do not drop when you push the clutch in. However, ever since the vibration started happening, starting from a stop is noticeably rougher than before. Before I could let out the clutch smoothly and the car would start out nice and smooth. Now, when you try to let out the clutch smoothly, the car stumbles a bit until it gets going.
Ok so the vibration seems to be getting a little worse and the car seems to running a bit worse. I'm really thinking it's the harmonic balancer, but honestly, I'm not very good with cars. So here's a final breakdown of how all this started. Dropped it from 5th gear to 3rd gear on the highway and floored it until redline. Then the car wouldn't hardly shift and the vibration began. The car shifts normally now but the vibration is still there. One clue as to what it could be is that when the car is in neutral at idle, the vibration is quite noticeable. If you rev it up a little in neutral you can feel the vibration slightly through the rev range. Now, if you push in the clutch and put it in first, the vibration goes away. Rev it up a little and you can't really feel the vibration, but this is only while the car is at a standstill and you're pushing in the clutch with the car in first gear. The car also still starts out rough in 1st gear. One other thing is before all this happened, the car was leaking coolant from somewhere near the water pump, like maybe the timing cover. I used some stop leak and it hasn't leaked since.
So I'm leaning towards a bad harmonic balancer. The car has 156k on the stock one I believe. The balancer does also wobble a bit. Also, is it possible the car is running kinda crappy because the timing is being thrown off by a bad balancer? The car used to start out smooth in 1st and now it's all shakey until you get up to 10 mph or so. Could this be the timing being off too? I'm thinking of taking it to a mechanic tommorow because I'm getting worried that I'm ruining my engine by just driving it around like this and ignoring it. Any ideas would be great.