AB-Oz

Hi all, hoping your collective wisdom can help me out here.

C4 is 1990 model, last service was in October 08, all new plugs, everything running sweetly.

Until a couple of weeks ago, occasionally while driving along it will lose power, revs drop to 500rpm I have to pull over to the shoulder until it clears itself and runs normally a few seconds later.

This behaviour could be very dangerous if it happens mid-corner or duing overtaking as you can imagine.

This week I have driven it to work every day, and it did it again yesterday arvo. This morning during the run into work it was fine.

Engine is at normal operating temps, no warning lights on dash.

It cant be bad fuel as I've refilled the tank (98ron) since the problem started, I'm suspecting maybe a fouled fuel filter?

Any ideas?

dfinnegan

I had that kind of behaviour with a bad O2 sensor in the rain.

dfinnegan

Pretty easy to test; just unplug it

Indycam

A clogged fuel filter kills the top end .
The fuel flow will not be good enough for full power .

Streetfighter

Just an idea, but have you cleaned your air filter? I had a similar situation last year and cleaned my air filter and so far no problems.

garrett376

You'll get all kinds of suggestions... how about another? I would place a good sized bet that it is your Air Flow Meter... if your car cuts to the point that you give it more gas and it does nothing, and at all other times it runs just fine regardless of operating temperature, then it is likely your AFM. Try to find a buddy to swap with since it's an easy item to take on and off to test. When I had a spare I'd lend it out for this exact purpose, but I sold it...

bwoodry

Check you coils.

I had a bad coil and car had similar symptoms was as if you turned off the ignition .


Bad Coil,,

garrett376

You can check your coils by simply unplugging one of them at the module (not the HT lead) - if your ignition is OK, the engine will idle fine with either one or both hooked up.

psiegel

I would also check and clean the ISV

911URGE

What? - noboody has thrown out the DME relay? I had intermittent power loss issues that turned out to be the DME relay.

dfinnegan

The ignition switch has been known to get flakey for some folks, too.
Try wiggling the key a bit.

Livefreeandrive

http://www.pcarworkshop.com/images/b...0590geolab.pdf

911URGE

Great suggestion

elbeee964

(Dang! -- Beat me tewit)
Ya've got to get up Pretty early to sneak one in before them Granite-staters!

AB-Oz

Thanks for all the suggestions guys, in summary:

1. Check the O2 sensor/s
2. check Air filter
3. Check coils
4. check ISV (whatever that is, google here we come)
5. check/reset DME
6. wiggle the key in the ignition! Really.
7. check for TSB on the AFM wiring harness.

I'll check all those, the car ran fine all day yesterday, go figure

As to No. 7, I am well aware of that as that TSB had not been done on my car when I first got it, and about 4 trips to the dealer still didn't pick this up. I finally found the problem and fixed it myself, thanks to the folk on this forum. I'll check that the dealer hasn't "undone" my work as they did one service, they removed the cable ties I had put on to keep all the wires nice and in the right place.