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I seem to have this hesitation at around 90-100km/h and also at higher RPM in lower gears, such as 3rd gear 60km/h. What it's basically doing is when cruising at 100km/h I try to accelerate and then all of a sudden the car will surge off. It's sometimes hard to keep a consistant speed.

I have cleaned at least 4 times the air/idle screw on the throttle body and once sprayed carby cleaner in the front of the throttle body. Today I have changed the fuel filter. Although it is smoother once the fuel filter was changed, it still has that hesitation.

Any ideas on what will fix this?

time for some new plug leads?

Fatty wrote:time for some new plug leads?

Replaced with Genuine Mazda leads back in September 05'. I'll get my hands on a Ohnmmeter to test them out.

I will go for the new plugs option mate, try a standard NGK or Bosch plug.

is the hessitation more of a stumble(flat spotting) or just a delayed response?

If flat spoting, then definately a fueling or ignition Prob.

If its a delay only, then may not be either.
but how much of a delay?

im not up to speed with your setup, B6 or BP, Mods etc.

if B6 then check the operation of the Vane Airflow meter,(or any other posible airflow restrictions) . It wouldn't be throtle body as it cable operated and you would feel any improper operation.

Cant hurt to change plugs if there nearly due, but your problem may be elsewhere if just a delay.

Also has the car lost any power?, is the fuel consump. higher than normal?

Rotary wrote:is the hessitation more of a stumble(flat spotting) or just a delayed response?

Delayed response. I have no problems at all going to redline in each gear though.

Rotary wrote:If its a delay only, then may not be either.
but how much of a delay?

Hard to explain. I need to keep pressing down on the accelerator and then it will suddenly accelerate.

Rotary wrote:im not up to speed with your setup, B6 or BP, Mods etc.

B6 (1.6L) with racing beat air filter, extractors and reguarly serviced, that's it.

Rotary wrote:Cant hurt to change plugs if there nearly due, but your problem may be elsewhere if just a delay.

Changed with NGK plugs not so long ago.

Rotary wrote:Also has the car lost any power?, is the fuel consump. higher than normal?

All seems normal....power may seem a little flatter

How is your fuel comnsumption?
If it is a little high, then I would be suspecting your o2 sensor is stuffed and Flooding when going into open loop mode (around 3500-4000 rpm or about 100K in 5th)

New sensor (single wire) is around $40 from Repco.

Do a search on here there should be part numbers somewhwere.

Cheers
NJ

ampz wrote:How is your fuel comnsumption?
If it is a little high, then I would be suspecting your o2 sensor is stuffed and Flooding when going into open loop mode (around 3500-4000 rpm or about 100K in 5th)

New sensor (single wire) is around $40 from Repco.

Do a search on here there should be part numbers somewhwere.

Cheers
NJ

I think you may be on the money here as that's exactly around the RPM it has been doing this. I had plan to replace this sensor once day as I heard it does make a difference when they are replaced.

I'll give this a go and get back on whether it worked or not

Check my write-up in the Tech Archive on installing a 4 Wire O2 sensor...

Boags'MX5 wrote:Check my write-up in the Tech Archive on installing a 4 Wire O2 sensor...

I can't seem to find it there and the 'search' is broken when used with your username! Do you have a link?

mr_rotary wrote:

Boags'MX5 wrote:Check my write-up in the Tech Archive on installing a 4 Wire O2 sensor...

I can't seem to find it there and the 'search' is broken when used with your username! Do you have a link?

The link in that thread got swallowed up by the interwebs... So the thread is useless. Just do a search on google for 4 wire 02 sensors on google and look for someone else's write-up.

Sorry to give false hope.

Agree with the above(O2), as its sounds like a very short delay,

Boags'MX5 wrote:The link in that thread got swallowed up by the interwebs... So the thread is useless. Just do a search on google for 4 wire 02 sensors on google and look for someone else's write-up.
Sorry to give false hope.

http://www.miata.net/hakuna/0004/h0001.htm

Does anyone have the Bosch model number, I can only find the NA6 in the Bosch online PDF manual?

If not, this may do the trick?
http://cgi.ebay.com/ebaymotors/O2-OXYGEN-SENSOR-BOSCH-Mazda-Miata-03-99-97-94_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQcategoryZ33557QQihZ022QQitemZ350035547624QQrdZ1QQsspagenameZWD1V

Finally got around to replacing the 02 sensor (single wire) on the weekend, made a massive difference! Now very enjoyable to drive