Rough idle

[Markus88]

Hi,

current engine mods: jb4 map 1, catless downpipes, coded out gpf/opf, ngk plugs with 0.22 gap.

every now and then there are rev fluctuations at idle and also when accelerating. is this due to the plugs or what else should i check ? ignition coils are oem and OK. Error codes: catless downpipes and code number 030e07.

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[antonio88x]

Probably something to do with the JB4 or a sensor.

 

[Benjilis]

I have the same issue as well but it’s only sometimes.
with my Jb4 I experienced it and with ecutek I sometimes experience it as well

 

[bigcat]

Does it happen with map 0?

 

[underdonk]

This used to happen to me with a stock ECU and only downpipe, exhaust, and aftermarket air filter. Does it only do it in a specific situation (i.e., cold start, warm start, temperature outside, sitting in the rain)?

Also, if I may ask, why did you do the NGK plugs?

 

[Markus88]

Without JB4 it’s the same. I did catless downpipe and gpf delete. Rough idle and rough rpms at any gear. It happens sometimes, not always.

 

[zrk]

I did catless downpipe

There ya go.

 

[Markus88]

There ya go.

is there a way to avoid this ?

 

[bigcat]

is there a way to avoid this ?

Yes, but your Supra is MY21, the easy way is change to another downpipe does not trigger CEL and coding to disable the OPF/GPF detection.

 

[Markus88]

Yes, but your Supra is MY21, the easy way is change to another downpipe does not trigger CEL and coding to disable the OPF/GPF detection.

the gpf detection is already disabled ? Is there a catless downpipe which doesn’t throw a CEL?

 

[zrk]

is there a way to avoid this ?

A tune would help. Seems the engine is trying to get to a certain RPM, and over shooting because the resistance isn't there from the downpipe.

 

[zrk]

the gpf detection is already disabled ? Is there a catless downpipe which doesn’t throw a CEL?

no

 

[Markus88]

no

ok then the only way is a flash tune. Or a custom JB4 map ?

 

[zrk]

ok then the only way is a flash tune. Or a custom JB4 map ?

Flash. JB4 can't do anything about idle speeds.

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