My Porsche Just Tried To Kill Me!

[diamondbluetarga]

My car is an 87 Carrera Targa.

Pulled out of a farm gate onto the A5 last night, with the 6pm rush-hour traffic going up and down. Put my foot down and... nothing. Coughed, spluttered, almost stalled, wouldn't go over 5mph and was almost rear-ended into oblivion by an artic.

Managed to get the beast onto some hard standing by the side of the road and panicked for a while. Engine revved ok when not in gear but then wouldn't pull properly when engaged.

I let it sit there for 20 mins, moved in backwards and forwards and then with a leap of faith pulled back onto the road. It stuttered and wouldn't rev briefly (as if the accelerator wasn't working) and then took off. Once up to speed, it seemed ok but was quite hesitant with gear changes. Got it home in one piece but a little nervous afterwards - never done this before and hopefully never will again.

Any ideas as to the problem? I thought it might be a fuel/fuel line issue, but as it is run on Super Unleaded from BP or Esso I would have thought it unlikely. I had put some fuel additive (similar to Redex) in 48 hours previously, but as this is exactly what it is supposed to cure I would be surprised if it caused it. It had also run fine up until then.

All thoughts much appreciated. Many thanks.

James.

[Sean Smallman]

At least you managed to get out of the way, its lethal the A5 if you can't hit it at speed.

Do 911's suffer with the DME like the front engined of that vintage?

There should be no need to use fuel additives if you are filling up with branded S+, they will clear everything that has deposited over the years without any help.

[sam]

If it was a 964 or a 993 I would say DME is a good start point , don't like the sound of additives though , I am sure you will have some pearls of wisdom soon though, which will sort you out . Good luck

[tr7v8]

If it was a 944 my guess would be Air Flow Meter (AFM), pretty sure these run one as well. The other option is throttle position switch but that'd give a screwed up idle.
Remove the air intake & see if the AFM moves cleanly with the engine running & being blipped, you can clean the throat with carb cleaner but be gentle!

[diamondbluetarga]

Yes, we live to fight another day... Have brimmed it with Super, just in case the fuel additive was what caused it to throw a fit. Should have diluted it now. I'm going to play around with it properly tomorrow and have my local friendly neighbourhood spannerman coming to help, so hopefully we'll sort it out. At least it doesn't sound like it is terminal. Many thanks for the advice.

[grbspeedster]

Check DME relay, under passenger seat.Always carry a spare with mine

[diamondbluetarga]

Mechanic ran it for 20-odd miles with no problems, plugged into a diagnostic machine and no faults coming up. Checked everything possible and seems fine now and he can't place anything wrong with it. How bizarre. Perhaps a poltergeist playing with the throttle? Quite happy if it has sorted itself, just hope it doesn't ever decide to do it again. First time I have ever had a problem with it, though. (Touch wood)

Thanks again for the suggestions.

James.