Hesitant acceleration and lumpy idle..!!

This is not a huge problem but it is bugging me a wee bit....

I have not driven the car much lately but I recently noticed that the car is "missing" whilst driving from cold, if you take your foot off the accelerator then it seems to be a bit lumpy.

Once up to temperature it stops this but there is still something not quite right. On acceleration it is a bit hesitant and then it goes as normal. This is always the case, press the accelerator the car pulls but not strongly and then a second later we are off and away (for an NA anyway...).

Finally, we started this morning and there was a strong smell of fuel on start up, the car hadn't moved for a week or so. All day the idle has fluctuated between a healthy 850Rpm and a very lumpy 500, at one point I thought it was going to stall but it didn't. I have just had it out for a 20 mile blast and it did actually seem fine..!!

Your opinions would be appreciated. My thought are either that the plug leads are breaking down (it had iridiums 12 months ago and since the I have done about 2k miles). A bad batch of fuel? Fuel filter blockage?? Dizzy cap?

It is due to have some oxygen sensors and plug leads soon but only as they haven't been replaced since I got the car..!! Would this have anything to do with it?

Thoughts anyone??

H.

I'd check the air flow meter (if it has one) or sounds more likely to be the lambda/oxygen sensor especially if it goes away when warm.

Idle control valve possibly needs a clean?

I would look at AFM, O2 sensors, and also check ECU water temp sensor, as if faulty this can make things silly rich by default.

Sounds very similiar to mine...when the engines warm it can idle really low, almost likes its going to stall as you mentioned! And i also get a strong smell of fuel at times, not in the car but near the back of the car!

It hasnt bothered me that much so havent done anything about it but will be nice to see if you can solve the problem for you...and for me

Also check you don't have a perished vacuum pipe

Also check you don't have a perished vacuum pipe

Very true, unfortunately its one of the obvious things i always take for granted that it has already been checked before asking for help:)

Thanks for the replies guys..!!

Where will I find the idle control valve and also the vacuum pipes. I'm out of my depth here so I reckon it's going to end up at the local garage...!!

I will take it to Manchester tonight and see how it goes. It seems to be using a lot of fuel but the guage was pretty low when I took it out yesterday. Will there be anything showing on the ECU as in fault codes??

I have never pulled this thing up from under the carpet as I have had two years of relatively hassle free motoring.....

H.

Thanks for the replies guys..!!

 

Where will I find the idle control valve and also the vacuum pipes. I'm out of my depth here so I reckon it's going to end up at the local garage...!!

 

I will take it to Manchester tonight and see how it goes. It seems to be using a lot of fuel but the guage was pretty low when I took it out yesterday. Will there be anything showing on the ECU as in fault codes??

 

I have never pulled this thing up from under the carpet as I have had two years of relatively hassle free motoring.....

 

H.

Sounds exactly like my mazda at the moment, i checked the fault codes and it came up with airflow meter and water temp sensor. Im trying the temp sensor first as its the cheaper option and am going to see if it helps remedy my poor idle when cold.

good luck

Sounds exactly like my mazda at the moment, i checked the fault codes and it came up with airflow meter and water temp sensor. Im trying the temp sensor first as its the cheaper option and am going to see if it helps remedy my poor idle when cold.

 

good luck

Oh and also where will I find the airflow meter.....

Hi Paul

If its missfiring on driving and your not using it much anyway, could be the fuel filter's clogged up. Could even be a problem with the fuel pump?? Have you checked the air filter's clear and the intake pipe's not perished/split (if you have an aftermarket set up, can't remember, sorry!) Get the garage to do a pressure test on all 6 cylinders.

The ICV has a 'diaphragm' - resembles a circular 'clip' - it's only 1.5mm thick so can break over time. That would affect your idle. i thought that was an issue with mine but it sorted itself out after a while It might just need a clean.

You can clean up your O2 sensors with a couple of yogurt pots and some lemon juice (leave 'em for 2 or 3 hours) worked a treat on mine (after you take the yogurt out)

Hope you get it all sorted soon anyway....although it could be sulking as your not driving it much these days

Lxx

When did you get your spark plugs changed?

When did you get your spark plugs changed?

pull out the plugs and check to see they are gapped correctly

Ok then,

looks like a worn dizzy cap and arm are the problem according to the garage. How much should this set me back wtihout the labour??

H.

Ok then,

 

looks like a worn dizzy cap and arm are the problem according to the garage. How much should this set me back wtihout the labour??

 

H.

I would contact Steve Manely for prices and look at doing this yourself, should be a fairly easy job and will save you a bit in labour

I would contact Steve Manely for prices and look at doing this yourself, should be a fairly easy job and will save you a bit in labour

Hi Wez,

Thanks for the reply. I expect it's a piece of pi$$ of a job but I really cannot be bothered mucking about for the sake of a few quid. The garage that does my stuff has always charged next to nothing for labour etc. They have ordered the stuff from Toyota today themselves anyway as they get the 15% discount that I get from Toyota in Wigan.

I just wondered if the Supra had an expensive dizzy cap and rotor arm as the last one I changed cost me a tenner.... That was on a Fiesta though.....

H.

Ok then, really getting pissed off now. I had the new dizzy ca and rotor arm fitted and the car has run perfect for a week.

Last night, the same problem has come back but much worse. On tick over the car sounds like it is bubbling and popping. When you plant your foot to the floor the car hesistates and feels like there is either moisture in the plugs or crap in the fuel.

This car has got to go to Le Mans in 18 days and I am worried. I think a new set of plug leads would be in order beyond that I wonder what it could be??

Where is the air sensor??

H.

Havard,

Just going through old threads and came across this one- did you get your car sorted and if so, what was the problem, mine is doing a similar thing?

Cloudder

It was the plug leads breaking down. I got a new set from Toyota £107.00 but it's been fine since..!!

H.