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The mkiv Supra Owners Club

Please help diagnose this engine performance / sound issue


The-Plethora

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I was driving along the other day when all of a sudden the car sounded like it was running on 5 cylinders, I stopped the car and checked everything over buts its still doing it.

It's really slow to accelerate and sounds quite loud and lumpy.

 

I have had all the coil packs out, checked them over along with the clips and all seems good. The RPMs seem to drop when I hold it at 1000 as in the video below, I took apart the IACV less than 6 months ago and cleaned it all out. Could this still be IACV related or is there something else I can try?

 

https://www.youtube.com/watch?v=TqYcIuso6Wo&feature=youtu.be

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Thanks for the pointers all, I changed the plugs about 4 months ago but will get some fresh ones as they are fairly cheap to rule out. It's hard to work on this in the week without garage or decent lighting so might try and borrow a garage in the week or do some more at the weekend. I plan to remove the IACV again and clean and change plugs.

This weekend I noticed a small coolant leak so spent some time gettign that fitted, I had the coil pack clips apart and removed and checked the white inserts and wires and all look ok.

 

One final thought on things to check, could this potentially point to a damaged O2 sensor?

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  • 1 month later...
Remove & then refit the plug coil connectors one at a time with the engine running and see whether one in particular has no effect on the rough running. That might narrow the search.

 

 

Cheers, that was it number 2 coil was knackered, I didn't want to mix and match so I bought a new set and it's running well now, thanks for the pointer :)

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