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Radiodanno

1999 Avensis - Rough Running When Cold

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Wonder if you can help.

In the last 3 weeks my car seems to be very subtly down on power. When we were away on holiday I felt the car struggle a little, but put it down to there being 5 of us and a boot full of loot. Now i'm back home and it's just me I'm confident something's not quite right.

The car runs rough when cold. There's no misfire, but the car will hop along if there's no accelerator applied. The second you apply some right foot the car will leap a bit and then be fine. This settles down once the car is warm - BUT is still apparent (less so) when hot. Let your foot off and coast up to a roundabout and you will feel the car more reluctant.

Also, I'm certain that the car has more go above 2,000 RPM than below. Much more so than when I got the car.

Obviously I may have more than one issue, but I'm after your help. I'll keep my ideas quiet for now as I don't want to lead you.

All help appreciated.

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Start with the simple things first - plugs and ignition cables. Could be running on only 3 cylinders. Get the car running and remove and replace each ignition lead in turn. use insulated pliers to do this to avoid shocks. If you have a faulty lead/plug you will find no difference when you remove and replace it. The car will likely stall when removing the others.

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Cars generally have two types of issue, Fuelling or electrical or both. I am more inclined towards fuelling. When was the last time you changed your fuel filter, spark plugs. Also get your ignition coils checked out. Air Filter is very unlikely never the less check if its compeleting blocked or very dirty. The fact that it run rough when cold (i.e. in condition where lots of fuel is required) and slightly better when warm, i would say its a fuelling issue. I dont think that your car has ht leads, i think it has ignition coils and you have electronically controlled fuel injection. It might be that your injectors are slightly bunged up. PUT SOME INJECTOR CLEANER. you can get this from asda, tesco, halford, you catch my drift? That would rule that out.

Keep us posted.


Regards,

Waqar

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New Air filter 2000 miles ago so it's unlikely to be that. Plugs are 4 years old but the car did lots of town work by the previous owner, so I'm changing them today. Original HT leads (14 years old) so more than likely that they've degraded.

I don't mind doing these, as there service items, but I'm not certain that it's going to fix it. Wondering about the fuel filter and the o2 sensor now.

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I think its a fuelling issue as i said before. BUT O2 sensors WOULD register a fault. This would result in CEL being illuminated and you would need an obdII reader to find out which one(s) you have. I have say something else here. you say that your car was driven around town alot, it might just be that it needs some injector cleaner with full tank of super unleaded and quick blast on a relatively higher rpm i.e. 3/4 000 rpm in fourth gear (I do not condone over speeding) and constant driving like this for about 20 mins should do the trick. It has worked wonders before it might work now. Its the cheapest solution out there also is officially known as the Italian tune up.

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I think its a fuelling issue as i said before. BUT O2 sensors WOULD register a fault. This would result in CEL being illuminated and you would need an obdII reader to find out which one(s) you have. I have say something else here. you say that your car was driven around town alot, it might just be that it needs some injector cleaner with full tank of super unleaded and quick blast on a relatively higher rpm i.e. 3/4 000 rpm in fourth gear (I do not condone over speeding) and constant driving like this for about 20 mins should do the trick. It has worked wonders before it might work now. Its the cheapest solution out there also is officially known as the Italian tune up.

Hi Waqar,

I responded with Radiodanno in another post (http://www.toyotaownersclub.com/forums/topic/151099-avensis-sr-t22-a-few-jobs/) and he has the pre facelift mk1. Your advice is good, and I would like to add that Radiodanno can use the jumper trick to find the codes, by using a paperclip or wire between terminals 4 and 13 on the OBD socket. Turn the ignition on but not start. The EML light will flash (Morse code style) the numbers of any faults. Two flashes, break then one flash - code 21 O2 sensor fault. Constant flashing without any breaks means no codes stored. Free quick and easy.

Fourth gear at 4000 rpm will just get you over 70mph so you will not exceed the speed limit by a large margin.

Radiodanno quick reminder to your earlier post, I did say to change the HT leads because after 14 years, they must be well degraded by now. I had similar symptoms until the HT leads were changed. May be clean or change the spark plugs too.

Once you have done the necessary changes, let us know what you have done and how the car is running.

Konrad

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New leads and plugs and things are infinitely better. I still think I'm down on power a titch, and it's got Shell 95 in it (not even Tesco)

What injector cleaner do you recommend?

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PS: Comma D-Tox cleaner is brilliant.

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