Fluctuating Idle

[MKVI_Guy]

I just picked up a stock 1991 E30 vert 141K miles. I have a few issues that I'd like to start tackling. Yes I've done some research around here but as my post count shows I'm pretty new.

• All of my gaskets leak very slightly.
• I have a fluctuating idle from ~900 RPM - stall.
• A harmonic rattle at low idle (as the car wants to stall) which seems to come from under the passenger seat.

Gaskets - I plan to monitor the oil level and replace
Fluctuating idle I plan on starting hose clamps.
Rattle I'll have it up on jacks this weekend and try to locate. Hoping something simple like a heat shield or exhaust hanger loose.

Long weekend ahead of me and the lady is traveling so I'll have some time to work on the car. Any direction/leads to get me going would be great.

Thanks,

[Gerta]

Hey welcome aboard R3V. The M42 has a bunch of maintenance related items that you should tackle. First, I'd consider looking at the timing components to see what state they are in. Also drop the oil pan and see if any of the inner bolts are loose. If you know the gaskets are shot, consider replacing all the belts and hoses too. Look up "Mess under the intake" as that will be very helpful. If you need parts, email steve@blunttech.com as he's a great resource for these cars.

[Gerta]

I also always recommend new M42 owners poke around M42club.com too ... between there an R3v you can always get good advice from forum members.

[ahlem]

Check for vacuum leaks especially at the bigger intake hoses.

[arams325]

fluctuating idle

your rattle is generally coming from the transmission when your idle dips super low and is about to stall that probably the jarring sound your hearing. is your fluctuating idle problem happening when cold or warm or all the time?

[MKVI_Guy]

Thanks All. Will definitely look into your suggested. I started with the major hose clamps. Seems to be running good now, but it is also much warmer out. It tends to give me more issues in cool weather.

Looks like the cat is going, found it held on by hose clamps. I think that's the noise culprit at the low idle. Think this will be replaced regardless.

Arams325, I noticed your also from CT as well. Mostly cold temps. Its running strong today.

your rattle is generally coming from the transmission when your idle dips super low and is about to stall that probably the jarring sound your hearing. is your fluctuating idle problem happening when cold or warm or all the time?