Distributer cap 4K miles, Thoughts?

[da Vinci Dan]

I am trying to resolve stumbling at 2500-3500 rpm. Starting simple and noticed that my distributor and rotor seemed very worn. Is this normal ware after 4K? I sanded down these contacts and the rotor. Will take it for a drive ASAP.

[da Vinci Dan]

[da Vinci Dan]

[ADDvanced]

[john walker's workshop]

Normal.

[da Vinci Dan]

Originally Posted by john walker's workshop

Normal.

Runs much better after sanding down the contacts but still not 100%.

Is that “normal” and replace or “normal” ... and look for something else causing the bucking at speed?

[da Vinci Dan]

Should I replace this with a new one or look for additional issues?

[kyngfish]

How old are the plugs? Wires?

May sound like a dumb question, and I only have my anecdotal experience to back this up, but have you made any other recent changes to your car?

I'd do the following:

- get it nice and hot, and then run it up to redline a few times in a safe space - I try to do this with my car once a week.

- doesn't hurt to replace plugs and wires as well as cap. Some people go for ultra premium wires, I wouldn't.

Do all of that progressively instead of all at once, to isolate the fix (if that fixes the issue).

I was getting occasional hesitation under load in the middle-upper rev range a while back, driving the s### out of the car fixed the problem, but YMMV.

I'll leave it to more experienced guys to dispense more advice.

[Tippy]

Assume a 3.2? This issue seems to be very prevalent.

[SalParadise]

What?!?!? Is URO making caps and rotors now?

Never mind, all the Bosch stuff seems to be made in the Peoples Republic of China anyway.

I had one instance just like this. It was a cap and a rotor that had about 1K on it on my Series Land Rover. For the life of me I could not figure it out. It really was the cap/rotor, even though it looked OK. Replace them both.

[da Vinci Dan]

Yes 3.2.

All plugs and wires were replaced 4K ago with cap and rotor.

[DanielDudley]

Stumbling can sometimes lead to the AFM, especially if it is always at certain RPMs. If you take it out on a long road, you can hold it in one gear and slowly work the throttle up and down through the RPMs. A stumble from the air flow meter will always be remarkably consistent. When you are taking it through the gears it will see more like a random stumble, but when you work it up and down the RPMs slowly it will always come in around the same throttle position and RPM.

[Bob Kontak]

Originally Posted by Tippy

Assume a 3.2? This issue seems to be very prevalent.

I don't think it is an issue. Dust off the cap contact points and move on.

[Tippy]

Originally Posted by Bob Kontak

I don't think it is an issue. Dust off the cap contact points and move on.

I meant stumbling in the 2500-3000 range.

There’s lots of threads on this including my own.

Never figured mine out after 6 months.

[DerkPerk]

Is that a Porsche cap or other?


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[da Vinci Dan]

Originally Posted by DerkPerk

Is that a Porsche cap or other?


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Porsche Genuine Part - $179.00

[T77911S]

just get a bosch cap.

sand or cleaning the contacts of the cap may only work once. tried it before. ran much better when I put new cap on but then mine had a LOT more miles on it than yours.
I think the gap from the rotor to the cap gets too big.

yours looks fine BTW.

as mentioned, could be tracks on the AFM, very common.

[da Vinci Dan]

Originally Posted by T77911S

just get a bosch cap.

sand or cleaning the contacts of the cap may only work once. tried it before. ran much better when I put new cap on but then mine had a LOT more miles on it than yours.
I think the gap from the rotor to the cap gets too big.

yours looks fine BTW.

as mentioned, could be tracks on the AFM, very common.

Thanks, T77911S. I am reluctant to open the AFM. AT this point, I think I will replace cap and rotor, clean out the throttle body, and give the engine a good look over for vacuum leaks etc... before diving into it. Also, at 70K I would think it is too soon for the AFM. No?

[T77911S]

check the torque on the intake bolts while you are at it.

[kyngfish]

Mine was getting sluggish in the middle revs due to carbon build up. Once hot and revving, it blew out a few clouds of black smoke under load and hesitating and stuttering, and then never had another problem.

This isn't to say there isn't an underlying problem. I'm fairly sure I have a small leak somewhere and that I'm running rich - which probably lead to the carbon buildup.

But she doesn't stutter or hesitate anymore.

3.2 here as well.