Occasional engine running problem

[YYC]

I need you guys' help to give some lights.
Engine: 6A12 NA
I experienced occasional erratic engine behaviour mostly after running hot for sometimes. The engine would run like loss of breath and feel some power loss, it ran not as smooth as it used to be. When I pulled over at the roadside, the idling was very rough swing between 200-1000rpm but not stalled. Disregarding the problem I kept on driving slowly @60-80km/h for 30mins the phenomenon disappeared for no reason. It ran smoothly again with full power for another 100km without problem until I got home.

This happened a few times over these 2-3 months. I didn't successfully send to workshop for diagnosis because every time I wanted to the problem disappeared on the way there. I felt like being played. wtf?

 

[twistedichc]

I need you guys' help to give some lights.
Engine: 6A12 NA
I experienced occasional erratic engine behaviour mostly after running hot for sometimes. The engine would run like loss of breath and feel some power loss, it ran not as smooth as it used to be. When I pulled over at the roadside, the idling was very rough swing between 200-1000rpm but not stalled. Disregarding the problem I kept on driving slowly @60-80km/h for 30mins the phenomenon disappeared for no reason. It ran smoothly again with full power for another 100km without problem until I got home.

This happened a few times over these 2-3 months. I didn't successfully send to workshop for diagnosis because every time I wanted to the problem disappeared on the way there. I felt like being played. wtf?

maybe it's sulking coz it's been sumtime tht u've pampered it e.g full carb overhaul:hmmmm:

 

[YYC]

Mech used to tell me that the idling is a bit erratic because of the less than ideal throttle body condition. Is this the cause?
Or some sorts of ignition related problem because it looked like the loss of fire in one or more of the cylinders which explains the loss of power?

 

[twistedichc]

Mech used to tell me that the idling is a bit erratic because of the less than ideal throttle body condition. Is this the cause?
Or some sorts of ignition related problem because it looked like the loss of fire in one or more of the cylinders which explains the loss of power?

from previoud thread, they say that if idling is not top notch 1st cause is Throttle body(TB), maybe check u'r plug 1st, if new maybe defect @ maybe the cable, it's worth checking out & it's quite easy i think:hmmmm:

 

[YYC]

I wonder if bad throttle body also affects other than idling because apparently it was rough and lost power during running.

Not easy to check plugs for my car, hell lots of job to remove manifold. The plugs are just about a year plus old and they are iridium.
Cable...hmmmm maybe because I replaced with a don't-know-what brand last time, was bought because of urgency to replace a defective one, not long after all remaining were swapped in.

 

[twistedichc]

QUOTE=YYC;1064270215]I wonder if bad throttle body also affects other than idling because apparently it was rough and lost power during running.

Not easy to check plugs for my car, hell lots of job to remove manifold. The plugs are just about a year plus old and they are iridium.
Cable...hmmmm maybe because I replaced with a don't-know-what brand last time, was bought because of urgency to replace a defective one, not long after all remaining were swapped in.[/QUOTE]

i'm thinking that, if u don't have time for mech 2 check it, may u should try diy checking anything that related to combustion of your car e.g. using on shelf additive wit u'r petrol such as discussed in adding 2t to petrol thread here, maybe u'll get some ideas.:hmmmm:

 

[papagoines]

got any spare ECU to try?

 

[vr2turbo]

I wonder if bad throttle body also affects other than idling because apparently it was rough and lost power during running.

Not easy to check plugs for my car, hell lots of job to remove manifold. The plugs are just about a year plus old and they are iridium.
Cable...hmmmm maybe because I replaced with a don't-know-what brand last time, was bought because of urgency to replace a defective one, not long after all remaining were swapped in.

Cable as in plug cable? If yes, check them because last time my wife's Hyundai I change them too, unknown brand and within a year they crack and leak current. One particular cable was near the metal part so was sparking to the metal part and had loss of power, but sometimes due to vibration it is further away from there and not sparking and have full power. Maybe not the same problem but worth a check....:hmmmm:

 

[Izso]

Intermittant problem like this usually wouldn't be a TB problem. If it was the TB the problem would always be there.

It's most likely your spark plugs, cables or coil itself.

Since your car is a 6A12, start with the cables first since easiest to assess, plugs next (good luck! Hahaha) and finally coil replace. Using those high intensity discharge cables will in the long run spoil your coil faster.

 

[Dayline668]

check MAF sensor...

 

[DanzEterna]

I also experienced the same problem if u use my car in the afternoon.
do check your spark plugs, plug cable & ignition coil.

 

[YYC]

i'm thinking that, if u don't have time for mech 2 check it, may u should try diy checking anything that related to combustion of your car e.g. using on shelf additive wit u'r petrol such as discussed in adding 2t to petrol thread here, maybe u'll get some ideas.:hmmmm:

2T to car it's new to me. Got the discussion thread but no time to read yet.

got any spare ECU to try?

No...

Cable as in plug cable? If yes, check them because last time my wife's Hyundai I change them too, unknown brand and within a year they crack and leak current. One particular cable was near the metal part so was sparking to the metal part and had loss of power, but sometimes due to vibration it is further away from there and not sparking and have full power. Maybe not the same problem but worth a check....:hmmmm:

Thanks for the tips. What you mentioned is very possible because the cheap cables I used.

Intermittant problem like this usually wouldn't be a TB problem. If it was the TB the problem would always be there.

It's most likely your spark plugs, cables or coil itself.

Since your car is a 6A12, start with the cables first since easiest to assess, plugs next (good luck! Hahaha) and finally coil replace. Using those high intensity discharge cables will in the long run spoil your coil faster.

So TB is ruled out. That's good!:top:
High intensity discharge cable? Are you referring to plug cable like NGK Racing Cable or something?

check MAF sensor...

If MAF sensor kacau, no engine check light alert?

I also experienced the same problem if u use my car in the afternoon.
do check your spark plugs, plug cable & ignition coil.

That's weird.
90% of the time engine runs smoothly.

 

[vr2turbo]

Thanks for the tips. What you mentioned is very possible because the cheap cables I used.

Mine also cheapo cable but never expected them to break down within a year...

 

[Dayline668]

MAF dirty or leak after the MAF will have erratic idle, old sensor still working then check light will not on, it will only on till its totally die.

In a way no harm in checking it out.

 

[Izso]

So TB is ruled out. That's good!:top:
High intensity discharge cable? Are you referring to plug cable like NGK Racing Cable or something?

Yeah. My old cables fried 2 coils of mine