Electrics: 850: Ignition Coil

[volvo2]

I did not change the coil. I think in my case that changing the cables and cleaning the distributor is what did the trick.

[Nick850GLT]

The garage had a look last week and were convinced that the coil was faulty, but also said there was signs of throttle body wear.
Just replaced the coil - guess what - no change. The engine is still running rough - it definitely judders as I ease the throttle down.
My thoughts, maybe wrongly, are that throttle wear might not help but is unlikely to have changed enough in a few thousand miles to explain the result, as the car was fine not that long ago.
I can't find much on repair of the throttle body either - and they don't exist new. All surprising if it is a real/common problem.

Just posting this hoping - I really am not sure what to do next!

[PSJVTHEBEST]

Nick,
Here is a list of what I did and you can tick off what you have already done.
- New MAF sensor
- All new vacuum hoses
- New distributor cap and rotor arm
- New plugs and leads
- New O2 sensor (Bosch) – there’s only one pre-cat
- New fuel pump and fuel filter – had previously checked fuel pressure and was c. 10 psi down. After replacements went up to c. 40 psi.
- Cleaned and serviced injectors (new seals and filters) – and see below
- Changed oil, filter and air filter
- new crankshaft position sensor
- new camshaft position sensor
- new radiator
- cleaned and service kits on injectors https://youtu.be/8rk0tKtiVic and ebay: volvo 850 T-5R injector rebuild kit 0280150 T5 Turbo
X5’)
- Replaced turbo control valve

I’m pretty sure my issues (similar to yours in some instances) were ultimately resolved by the replacement TCV from Dancake but that was probably the last piece of the jigsaw of other contributory factors solved by some of the work listed above in my case. If you are pretty sure that the spark is good, have you checked the injectors (see above)?
Final resolution was confused by me putting on a non-Bosch MAF sensor earlier on in the (mis) diagnosis process!