Hi Guys,

Hoping for some diagnostic help.

Replaced all 6 spark plugs this weekend with Bosch Platinum IR Fusions and I'm having some serious issues.

Initially the car started OK, but then around the block I'd get some serious shudders, then when I'd floor it, it would accelerate then suddenly lose power and drop to below 1k revs. I left it for a bit started it again, did the same thing and eventually lost all power.

Parked the thing and eventually it started and now had the ignition light on amber when driving, with the same symtoms.

Any diagnostics would be helpful.

Cheers

Smithy

Just an update, I've replaced the front 3 with NGK standard plugs BKJRE 11's or whatever they are and it seems a bit smoother, checked the cables etc.

The inigition light is off now as well.

Still not convinced but.

Might need to adjust the gaps on the BOSCH F1 6's?

did you disconect the battery when you did this as car will run rough as it resets the ecu

Yup battery disconnected.

It does seem like the ECU trying to figure everyhing out, took it out for another drive just then, seemed a bit better. I'll see how it goes.

Cheers

yeah mate takes a little while to learn again will want to stall etc so was not the plugs just take for a drive and all will be good will happen every time you disconect battery

If it is just the ECU needing to recalibrate, the quickest way to let the ECU recalibrate is to start by letting it idle with the A/C off for at least 10 minutes (if engine warm) to 15 minutes (if engine cold). Then go for a drive where you won't have too much start/stop action and will be at a relatively constant speed (60-80kmh).

However some of the behaviour you describe is symptomatic of a degraded/failing ignition coil (especially as this started when you changed plugs). If the behaviour doesn't clear up with some running, you might want to have the distributor (which includes the coil) and leads checked out.

Just an update, still no better this morning, I've tested the leads put the multimeter to 20k and almost every lead gave me different resistance, which isn't right? I tested the front 3 and got 6.12 for the first 9.28 for the second and 5.12 for the third.

I'm going to replace the cables and see what happens.

It's normal for variations in resistance to occur. Different lenghts will produce different resistance, I would say that those ignition leads are within the allowable tolerances.

In you original post you said "now had the ignition light on amber when driving", which indicates to me that the alternator is not charging and the car is running off the battery at reduced voltage which the ECU will not like. Your battery is now probably close to dead flat.

Might need to adjust the gaps on the BOSCH F1 6's?

I don't think your meant to change the gap on those type of plugs. They are factory set and changing them may cause damage. Just check the gap.