Engine miss on the 4agze

[heshan]

Hi guys,

I was out of the country for a few weeks and after I got back I didn't drive the car for a month or two so in total the car was idle for abt 4 months.

Now after I took the car out, there's a miss when I try to rev aggressively. I notice that the miss comes badly when I try to go beyond 0.5 bar boost in the super charger.

During this miss the car puts out the check engine code but I used to get the check engine without this issue as well so not sure whether its related BUT, after the check engine light comes on I feel the car reduces the missing slightly.

The missing majorly come before 3K RPM and reduce to an almost 0 after 3K.

Recently i changed the fuel pump to a 255LPH walbro and my sparks should be changed as well but can anyone tell me whether this could be related to either before I do something about the 2 possible causes.

Shall I do a throttlebody cleanup?

Any help would be greatly appreciated.

thanks.

[heshan]

Help?

[NoHachi]

Could be anything.

What check engine light? A check engine light is usually an issue, even if you don't notice it straight away.

Doubt its the throttle body

[heshan]

could it be my spark plugs? I haven't replaced them in a while and its time I replace them. Over here it cost 100 USD so I'm a bit stingy to replace them so been pushing it day by day but should I change and see?

Is there any more info you'd need to diagnose?

[allencr]

heshan Wrote:could it be my spark plugs?

Yes,it could be, also old petrol, plug wires, cap or coil/ignitor.
Spark plugs can be cleaned/wire brushed, filed & gapped.
Use .5mm gap if you think it may be a weak coil. Also helps with bad wires & cap, that are taking the path of least resistance.
DO NOT buy plugs because of advertising BS!!! No multi-ground iridium copper crap, just the factory recommended platinium for long life or steel for1/5 life.

[heshan]

hey thanks allencr.

Actually I forgot to mention this; the lead coming from the coil to the distributor has broken at the end that connects to the coil the wires have been exposed and stuck into the coil's connector but this is how it was running for a while now so I didn't think this might be an issue.

How do I replace this cable as this doesn't seem to come with the spark plug leads sets advertised on ebay.

As for the plugs I was planning on buying DENSO IQ20s which was said to be the recommended iridium plugs for the car. Should I buy this?

[Ivan141]

Replace that cable first.. I'd go looking at parts stores, it's a regular ignition cable, you just need to get one in the correct length.
I wouldnt waste 100 dollars just on sparkplugs... you're not running some monster turbo engine with special needs.

[heshan]

Is there's impedance I need to check or any ignition cable with the exact length? Can it be slightly longer or shorter?

As for the spark plugs I'm going for Denso PQ20R which seems to be the OEM plugs which costs half the iridiums.

I'll get a pic of the cable here so that I can find out if I can repair it.

Thanks guys. Appreciate all your feedback.

[allencr]

30,0000+ volts doesn't care about kind or condition of the connector. Any gap will easily get jumped, but it will arc & burn/melt & grow larger & eventually look for another path to ground with less resistance.
Some old resistance wire designs -RFI- radio suppression stuff made of carbon & string- always needs a decent connector, while the newer stuff with a spiral wire inside last a while before causing misfire & burning & failing completely.

[Gtsi-R]

also check the altenator.. if it is providing enough voltage

had the problem aswel, after i exchanged the ignitor cables a year back..
in the beginning i missed a few fires when asking for power..

there simply wasnt enough voltage to ignite at sc pressure,,

over time it became worse, my alternator was worn. so had it refurbisched.

good luck!