Very rough Idle while in gear A/T

**thegen58** · 01-23-2012, 01:02 AM

Hey guys I have a problem that I think I have tracked down but would like to confirm or get opinions on other things to check before I go buying parts. I have a 99 spyder 2.4l that has a pretty rough idle, not up and down or to high or to low but just vibrates real bad. You can feel it at idle only and is pretty bad at stop lights in gear etc. When the car is in park or neutral its not so bad but you can still tell its there. By listening to the exhuast its sounds like a slight miss almost. I have checked the general maintenance stuff such as plugs, wires, fuel filter and air filter. Once all that was done I went ahead and plugged in the ole autotap to find that in park with no accesories on, the timing is retarded between 9 and 11 degrees in relation to #1 cylinder. Now the sticker on the firewall says to check this in park with no accesories on and the idle at 750 plus or minus 50 wich is what all that was set to. Could I have jumped a tooth somehow? or could have someone incorrectly installed the timing belt incorrectly? As another note the car threw a p0421 cel catalyst warmup time under threshold last week, so I took it to the exhuast shop where they used a temp gun to check the cat and said the heat was equal all the way through. My understading is that the output side should be hotter than the input but this code can also be caused by a bad rear o2 sensor as well. Any advice would be greatly appreciated. Thanks in advance guys.

**thegen58** · 01-23-2012, 12:52 PM

Oh and I have also checked for vacuum leaks as I know that it is in relation to the timing and found nothing. Granted I didn't do this with a gauge but with a can of TB cleaner to see if the idle would change, thanks again guys.

**A.D.D.** · 01-23-2012, 03:45 PM

Check your motor mounts.

**7inchexhaust** · 01-23-2012, 08:42 PM

It only idles bad? How does it drive? What kind of mpg are you getting? If you're worried about the mechanical timing being off, pull off the timing cover and take a peek. It's a SOHC so it is a lot easier.

**thegen58** · 01-24-2012, 04:17 AM

Thanks for the replies! As far as motor mounts go, the front one was shot so I replaced it and dramatically improved these vibes. I know the drivers side is not in great shape but this whole kinda puttering sound (slight Miss) I hear from the ehaust is why I started looking elsewhere for a source of these vibrations. As far as gas mileage I figured it to be around 17 mpg. Driveability seems fine to me, plenty of power after idk 1200 to 1500 rpm on up. Yes it only seems to be at idle and not nearly as bad in reverse as drive. Thanks again for the help guys I really appreciate it and hope I don't sound to retarded lol. Also will be ordering that other mount asap since I know it wouldn't hurt to replace it. The whole timing showing at 11 degrees out at idle on the computer is what concerned me, should I even be looking at that as a way to see what's going on with the timing?

So I also did some research while looking for new motor mounts and came across poly inserts which led me to about a billion "how to repair a broken motor mount with 3m window weld". What do you guys think about this? I read a few write ups about it and it doesn't sound like a half bad idea in theory anyway.

**7inchexhaust** · 01-24-2012, 10:17 PM

Originally Posted by thegen58

So I also did some research while looking for new motor mounts and came across poly inserts which led me to about a billion "how to repair a broken motor mount with 3m window weld". What do you guys think about this? I read a few write ups about it and it doesn't sound like a half bad idea in theory anyway.

Merc has done it personally, so hopefully he will reply to this.

Also the driver's side motor mount is the one that usually busts on the 2g's, and also an important one.

**A.D.D.** · 01-24-2012, 11:44 PM

i did the window weld in conjunction with the poly insert and it worked pretty well but i have since moved to solid mounts for front and rear roll stops.

**thegen58** · 01-24-2012, 11:51 PM

Sounds about right, upon further inspection I have noticed that one time the drivers side mount will be pushed all the way forward and other times be all the way towards the rear so it must be in bad shape. I haven't looked at the rear mount and it's been so long since I really been elbow deep in one of these engine bays that I can't remember the difficulty of r&r on that one or Trans mount. Guess it sounds like I will be finding out soon enough though lol. If this doesn't eliminate the problem then I will definitely be looking into other things. Hopefully someone who knows a good process of doing this $20 fix will see this and chime in. Thanks again!

Sorry bout that A.D.D. I must have been typing when you posted that. Good to hear from someone who has done this personally. So did it hold up well when you had it in there? I have read some people had issues with cracking. Some say to bake it for four hours at like 160°. But I don't know about putting that $hi# in my oven lol.

**A.D.D.** · 01-25-2012, 03:13 PM

i put it in with the insert for the front so i dont know how much more it helped. but i do know the mounts helped alot with the way my car launched at the track.

**thegen58** · 01-27-2012, 03:51 AM

Ok guys the motor mounts may have something to do with all this but my girlfriend took the car to work today and then I got a text saying that the ses light came on and the idle was worse than before. Got to the car and it's barely idling, code was p301, changed plugs and wires and no change, pulled injector clip off #1 while running and no change in idle, pulling the plug wire off did make the idle worse though (weird). So the car isn't sounding to hot it def has a full blown misfire and what now sounds like a knock from where the head meets the block almost sounds like it's outside the motor but it's not. This only happens when you accelerate so I'm lost here. I would think a spun bearing or bad wrist pin would knock even at idle, as would a stuck valve. But a bent valve or bad lifter on the other hand? It def on the exhaust side of the motor for sure. Any advice would be greatly appreciated. Btw the spark looks plenty strong.

LinkBack

Thread Tools

Display

Very rough Idle while in gear A/T

Posting Permissions