Gentlemen,

As the title reads, I have an intermitant missfire that is getting more agressive every time I use the car. It has now got so bad that I lurch down the road like a kangeroo. I can use high revs to get past it, but can feel that it's down on power for a couple of seconds, then the power comes back to normal. On the approach to junctions/roundabouts it occasionally just dies on me, and I restart by selecting second gear and letting the clutch up as if jump starting the car.
It usually happens at between 2 and 3k RPM.
I have cleaned the ISV, and checked the dist belt, both being OK, although I could do with new dist caps and rotors. I have swapped DME relay and had the car 'hammered' and no fault was found.
I put a fresh tank of Optimax in 2 weeks ago, so the gas isn't old. The problem has been there since last autumn but I hardly use the car in winter. It is garaged.

What do I try next?

Thanks in advance,

Mark 90C2.

 

If you know you need new caps and rotors, I'd start there. I had erratic idle and stalling when I got my car and it was the dist. caps / rotors. It might not be the cause, but it's worth ruling it out if you know you need them anyway.

 

Dave,

I have ordered them already, and they should arrive tomorrow. In the meantime I'm to be seen in central London doing a Basil Fawlty, and beating my car with a branch!

Mark.

Bit of photograph at the weekend, Dave?

 

I'll watch out for you - I seem to have to travel through most of central london today to get to JZ by train!

There was some photography at the weekend - most wasn't terribly successful, but I liked this one and a couple of others.

 

I have the same problems before and they turned out to be the defective ignition coils. Changed them and it solved the problems. I do get stallings at stop light once in a while, but I think idle adaptations with a hammer will solve it as well. Good luck. Andy

 

Andy,

Thanks for the reply. Is there a way to test the coils without getting zapped ?

Cheers,

Mark.

 

Hi Mark,
I bought a spark tester from a local auto parts store here in Washington D.C , USA, and hooked one of the plug wires onto the tester. I then clipped the tester onto a grounded part of the engine and have someone else cranked the engine and looked at the color of the spark on the tester. If it has anything but violet color sparks, the coil is weak. You can also borrow a set of coils from a fellow 964 owner and swap it out. It took only a 15-20 minutes to swapped out the coils. Andy

 

Andy,

I'll try to pick one up tonight.

Cheers

Mark.

 

Mark - if you don't find what you want, PM me. I changed my coils a couple of years ago when I was having running problems. The new ones made no difference (was the Air flow meter in the end) so I know the originals were OK. I assume I can find them again, and you are welcome to borrow them to trouble shoot.

 

Before you do any of that, disconnect the negative cable at the battery and clean both ends of it, the battery terminal and the terminal on the body where the negative cable attaches. I had exact same symptoms as you describe and that's what cured mine.

 

I agree with Dave - I had exactly these symptoms and eventually tracked it down to the air flow meter - definitely try this before everything else - get your mech to swap it out for a working one. Mine was duff even at 1 year old. I tried rotors, coils, WOT, leads, fuel cap, filter, etc etc and now with new AFM it is fine! Let us know how you get on. BTW I needed a new clutch after all the kangarooing wrecked it! good luck.

 

Morning !

I cleaned both ends of the negative last night and it made no difference. Couldn't get a spark tester yesterday, so I will try again today.
Dave, I may take you up on that.
Brookweb, a new clutch!....Are you trying to push me over the edge ?

Cheers,

Mark. 90C2BalticBlueKangeroo.......!

 

I don't think you should fix it now. 90C2BalticBlueKangeroo has quite a ring to it - if you fix it, it'll just be "90C2" - that's a lot less cool!

 

Dave, believe me, it doesn't look to cool driving down the street!!!!

Cheers,

Mark.

 

Gents,
Is there any point in testing the spark before I change my knackered dist caps and rotors?

Cheers,

Mark.