Bad miss under acceleration 2002 corolla

[RAZA]

Hi team,
I have a 2002 corolla (e120?) With the 1.5L engine.
It has developed a fairly bad miss under acceleration between 1000 & 3000rpm. It idles fine, and once past 3000 it is fine.
It improves once the car is up to temp, but It's particularly bad for the first 5 minutes after a warm start.

Google and my guess agree there are a few possible causes.
- afm
- o2 sensor
- fuel supply (pump/pressure regulator etc?)
-plugs etc

Rather than start replacing these 1 by 1 and inevitably find out the problem is the last thing I replace, does anyone have any suggestions on how to isolate the problem?

Tia

[GDII]

Coils can give up on these engines. I assume it's the 1NZFE based on the 1.5litre capacity.

Spark plugs are good to just replace anyway. You can pick between the 5 types of DENSO or NGK
http://www.globaldenso.com/cgi-bin/glob ... ion=search
https://www.ngk.com/product.aspx?zpid=9326

[xsspeed]

Sounds symptomatic of failing coil(s)
Are these coil on plug?

[RAZA]

Thanks for the replies. It is the 1nzfe.

Any suggestions on how to check the coil packs? unplugging them one at a time while at idle doesn't tell me anything as it runs fine at idle. Am trying to avoid buying new ones then finding the fault lies elsewhere.

[matt dunn]

Going from your explanation it really sounds like a failing coil.
They are hard to tell which one though.

Sometimes it is just as easy to get one, fit it to cyl 1 and try it.
If not fixed try cyl 2, then 3 then 4 etc.

OR see if there is a fault code in the system,
possibly not though from a coil fault.

[RAZA]

Ok cheers will get hold of a coil and give that a go.

[Flannelman]

Plug gap.
Got a BA Falcon that had the same issue. Stutter when cold, got better when hot. Guy replaced coils and was still there.

Gap was 1.7mm!

[matt dunn]

Plug gap.
Got a BA Falcon that had the same issue. Stutter when cold, got better when hot. Guy replaced coils and was still there.

Gap was 1.7mm!

Thats a common issue on the Falcons, as the factory gap on them in either 1.3 or 1.5mm from memory,
and the coils have a weak arse spark anyway.
We always put in plugs with a more standard gap than spec on them.