Hi Guys ive got a TT Auto and it seems like its idling on 5 cylinders then when you drive it over a certain rpm it seems ok until im waiting at lights or junction and the revs drop to which its lumpy again and some times stalls. What should I be checking that could cause this issue.......Car was serviced tonight with all fluids/filters & plugs but no difference? Thanks Taff

Maybe bad gas?

 

 

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Use 93 or higher octane for sports cars such as 300zx and stuff like that

 

 

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One of your injectors is out. Check to determine which by unplugging the coil packs, one at a time with the engine running, until you notice a drop on the RPM's

not gas as i always use 99RON fuel and il check that Robsz Thanks

Use 93 or higher octane for sports cars such as 300zx and stuff like that

 

 

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You don't get Octane that low in the UK. 95RON is standard.

With 98 and 99 RON available.

Sadly these are always difficult to disgnose as it could be a bunch of thing. Fouled spark plugs, injector, incorrectly set timing, air leaks.

 

If it's a fairly recent issue and was driving fine previously, I'd start with the above comment on pulling the coil plugs to see if a particular cylinder makes no difference, also check each of these plugs for corrosion. If it is a particular cylinder, you can then check the spark plug and injector associated with it to see if they're okay/within spec etc.

I had a same thing happen on mine. Turned out to be an air leak after so it wasn't gettign the right air to fuel mix. One of my recirc valves had a big ol hole in it :D Got to the point where you coud hear the air leak when engine was running,

You don't get Octane that low in the UK. 95RON is standard.

With 98 and 99 RON available.

 

That's even better then 93 octane in Canada 93 is the max

 

 

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just had serviced with new plugs. oil,AT fluid,filters etc but no difference in lumpty at low revs......I will start checking all of the other above and keep you posted ;)

You don't get Octane that low in the UK. 95RON is standard.

With 98 and 99 RON available.

 

That's even better then 93 octane in Canada 93 is the max

 

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USA measurement is AKI.

UK measurement is RON.

 

93 AKI is the equivalent of 99 RON.

 

All moot, however. Doesn't matter what flavour of pump fuel you have in the tank, it wouldn't be the cause of an irregular idle.

Edited March 19, 20169 yr by Noz

Mine has a similar problem, lumpy on idle, then seems to pull alright once going. Its been diagnosed as the timing being out. Ive yet to fix it, so cant confirm anything yet. However you might want to consider that?

I had an injector stop working after running ok!

 

easiest thing to do first is ;

 

Long screw driver stick it on the injector see if its clicking with engine running. (one of many things ticked off) OK?

 

If OK move to next easiest.