Pain-in-the-ass Micra

[rlees85]

Been wanting to do a few mods to my micra to gain a horse or two, but the biggest improvement of horsepower i could gain is by fixing this on-going problem where the car keeps mis-firing at high-rpm.

I've noticed now that if ive been driving for a long time at high-speed (say spent an hour or two on a motorway) then the mis-firing goes away completely for the rest of the journey, but it starts again when i use the car next.

It starts to misfires at round 5,500 RPM in 2nd, 5,000 RPM in 3rd, 4,500 RPM in 4th and id say around 4,000 RPM in 5th

Idle is sometimes slightly lumpy too...

I've tried:
New sparks, Tested all ignition coils, Feul Filter is fine, ran some redex through the tank (twice), changed the oil and used engine cleaner.

I was thinking it could be any of the following:

Temprature sensors giving the ECU the wrong temprature
A Feul Injector
Lambda/o2 Sensor
MAF (Throttle Body)

also im getting alot of timing chain rattle, could it be that? even tho its only done 40k miles?

Basically i was wondering if theres any thing on that list that it probably wouldnt be?

Cheers guys, and sorry for the long post.

 

[Glenn]

if the car cuts out then it is almost guarenteed to be the throttle body, there are many posts on this thought if that is the problem

 

[rlees85]

cheers it doesnt cut out tho, not even nearly..

 

[rlees85]

drinking loads of oil too at the minute, could be down to city stop-start driving tho.... :S

 

[59 bhp is more than enough]

i know this sounds really stupid and i dont wanna insult you but are all the ht leads in and secure. mine soes it sometimes where they just come a bit loose.

 

[rlees85]

lol i dont have much mechanical knowledge so dnt worry bout insulting me, mines the facelift micra which uses individual coil packs rather then HT leads, and they've all been tested and are secure.. cheers for the reply tho

 

[rlees85]

ok sorry to revive a dead topic but i found the problem is the air flow meter. Theres no way i can afford a new or reconditioned one right now, how hard is it to take it off and clean the hot wires and resolder the joints (as shown in the aussie guide)? also, is there a point?

thanks!

 

[hughes_16v]

resoldering is easy, just hard to explain without diagrams and pictures of the connections

drinking loads of oil too at the minute, could be down to city stop-start driving tho.... :S

or you have a leak or valve seals maybe duffed, if the problem with drinkin oil still exists, put your hand near the exhaust pipe and get a friend to give the car some right foot, if your hand as oil spits on then the valve seals could be duffed

or if your not the sort to want oil on your hands, get your friend to stand at the back of the car!! lol

 

[Stuart]

i got a 2nd hand TB from the scrappies. ok there's no garauntee on how long it'll last but mines last a couple of years now and cost me around £40
try that...

 

[Allan]

I had a mis-fire for 10k miles. Turned out to be a spark plug lead.

I tryed spark plugs, new throttle body and several other things before the leads.

 

[Stuart]

any luck so far? doesnt do an engine good to be run like that

 

[rlees85]

cheers for the replies, i havnt had a look yet, i will have a good look later on today or tomorrow. i havnt used the car much at the minute so it should be okay. There is no oil leak and its not using much oil now either, i think i must have been driving to 'enthusiastically' around the time of that post lol!

i came to the conclusion its my throttle body acting up becuase i uplugged it and took it for a quick run, and it never misfired at all, went really smoothly thru the higher end revs, without loosing power.

Would you say its probably the throttle body aswell from that information? Thanks!!

 

[rlees85]

surely with all the throttle bodies that play up on these forums some1 should know if thats a fair way of diagnosing (see above) the throttle body??

cheers!

 

[59 bhp is more than enough]

if its idling really bad and starting is sometimes a pain then people tend to re-solder the throttle body in hope this will fix it, which most of the time it does there is a guide on how to do it here.

http://www.micra.com.au/information/nissan-micra-articles/cg13de-throttle-body-resoldering-guide.php

pretty simple really, tookme bout 15mins if that.

mike