FLAT SPOT PROBLEM!

[Anonymous]

Hello Guys

I have a strange issue.  If I accelerate hard in every gear, I get smooth acceleration all the way through to the red line.  If I have to balance the throttle for whatever reason, say sitting behind a car waiting for a moment to overtake, and then I floor it, acceleration is smooth up until about 5,000 rpm and then it flat spots.  I get through it eventually, but acceleration is very weak.  Also, if I am driving the car normally (at about half throttle), it pulls smoothly up until about the 5k mark and hits the flat spot again.  I have done various searches on the forums, and there are similar issues to mine, however they all differ in some way.  Could it be a faulty MAF sensor, as this seems to be the closest match that I can get.  If it is possible, is there anything I can do to test it without buying a new one first?

[northernalex]

first thing for you to do is just pop the maf out and clean it with a little carb cleaner, that may clear the problem.. THe torque dips slightly after 5-6 anyway.

[Anonymous]

Thanks for that.

Being a bit of a rookie at this sort of thing, where is the MAF, and how do I remove it?  I also don't know if it is worth mentioning, but she is using oil at quite a pace.  I think it's it has drank about a quater of the dipstick in less than 500 miles.

[northernalex]

the maf is a on the pipe vetween the air box and the engine, it has a cable connected to it. There is two screws on the top. If you do a search for MAF and CLEAN there should be some instructions somewhere.

The high oil use is a tiny bit worrying, check out the pre-cat informationt hread, and try not to worry it may be nothing.

[Anonymous]

will have a look now.  cheers alex

[Anonymous]

Keep checking the oil level.  You could inspect the precats in the manifold (still have them?) for peace of mind.

[enid_b]

as the others have said, it sounds like a dirty maf.

whilst you are doing that, unplug the battery for 30 minutes. this will reset the ECU and should provide a boost in performance.

Also, as mentioned above, check and remove them nasty precats as a matter of urgency.  they are a ticking time bomb and no mistake.

E

[Anonymous]

Please, please, please read up about the pre cats.

Even if they arent the problem you want to get them ripped out.

Take it from someone who knows  s:evil: :evil: s:evil:

[Anonymous]

what are the pre-cats and what is their purpose?  If I remove them, will it still pass MOT emissions testing, or will I have to do something to get it through?

[aaronjb]

 m http://www.mr2roc.org/phpBB2/viewtopic.php?t=11393 m

[spit]

See the Sticky thread(s) at the head of the topic list in this forum. MOT is not affected.
(*edit - beaten to it by the wise one. Good work, Aaron  s:wink: :wink: s:wink:  )

[Anonymous]

Cheers Guys - couldn't see the wood for the trees!!!!

Have checked the MAF sensor, and while it was filthy, a clean up didn't sort the issue.  Next step I think will be to speak to MR-T and see what their computer fires up (if anything).  Have just ordered the O2 removal socket so will check the pre-cats (nasty little things) when it arrives.  I was going to replace the exhaust at some point, so it looks like it may be sooner rather than later - don't know whether or not to replace the manifold at this stage but the bottom line is those wee beasties are going one way or another!

[Anonymous]

OK - next question.  I have just had the car on toyota's test rig, and they say I need 4 new coil packs and a set of spark plugs.  Does this sound right?  I have only just had the thing serviced (by a non-toyota dealer) who stuck a set of plugs in it.  I'm told the bill will be about ... cough ... £450 all in.

So as I'm spending a bucket load on stuff that I really don't want to, are there any performance alternatives to sweeten the deal or am I stuck with the MrT standards?

[Peter Wright]

I wouldn't trust anything any Toyota garage said to me
Sorry
  s:o s:o  
 Pete

[markiii]

highly doubt it's all 4 coilpacks

do tehe plugs yourself and see if it helps

[Liz]

How far to Essex from Suffolk are you, you could try my MAF in it to see if it makes a difference?

[Anonymous]

Hi Liz

I'm picking it up tomorrow morning in its non-fixed state from Hills at Bishop Stortford.  I also only live in Haverhill, so you're not massively far away.

[Liz]

Can do Sunday if you want?

There is a good ex toyota mechanic in Haverhill - John Cox - he has agreed to gut pre-cats as well at a good price.

[markiii]

or come to mine tommorow, since Liz and Si are here anyway, I'm only in welwyn?

[Anonymous]

I must admit, I do have my doubts on the coil packs, but then I don't suppose there is much I can do to check them other than to replace them.

I would like to try another MAF, as that is my gut feeling, but sometimes it is quite intermittent.  Cheers for the offer markiii, but I think tomorrow may be out for me.  I can do Sunday though if the offer is still on the table Liz.  Bocking isn't far and it should be a nice day for a drive.  May also get details of the Haverhill Toyota bod if you have them, as I need the pre-cats doing anyway.  Not a job I fancy myself!

I should be free all day, so I can work to whenever suits you best

[Anonymous]

I must admit, I do have my doubts on the coil packs, but then I don't suppose there is much I can do to check them other than to replace them.

I would like to try another MAF, as that is my gut feeling, but sometimes it is quite intermittent.  Cheers for the offer markiii, but I think tomorrow may be out for me.  I can do Sunday though if the offer is still on the table Liz.  Bocking isn't far and it should be a nice day for a drive.  May also get details of the Haverhill Toyota bod if you have them, as I need the pre-cats doing anyway.  Not a job I fancy myself!

I should be free all day, so I can work to whenever suits you best

[Anonymous]

not quite sure how I managed to post that one twice     s:oops: :oops: s:oops:

[mr2mark]

£450 eeeeccccchhh how do these people sleep on a night .. I cant see it being even 1 coil pack because it would be misfiring . For £450 you could probably fill the tank, travel up here to newcastle I could fit all 4 coil packs and spark plugs(in about 7 minutes) and you could drive home with another full tank and probably fill your tank again when you got home !!!

[Liz]

No problem - you probably have driven past my house on the way there!  Will pm you with address.

[northernalex]

£450 eeeeccccchhh how do these people sleep on a night .. I cant see it being even 1 coil pack because it would be misfiring . For £450 you could probably fill the tank, travel up here to newcastle I could fit all 4 coil packs and spark plugs(in about 7 minutes) and you could drive home with another full tank and probably fill your tank again when you got home !!!

Yeah but youre a star Mark!  s:) s:)

Wanna fix my crappy 106 diesel with a leaky fuel pump?  s:) s:)