Weird Revving HELP!!!

[TieNN89]

Not sure what to put in the subject so yeah

Anyway for some reason only just today has my engine been like its out of fuel

There is fuel in the car I filled it up yesterday to Full and only done 80km since

While I'm driving with the Revs down low 1500 - 2000rpm my rev cuts in and out

so I stop to the side of the road and put her in Neutral and rev up slowly and theres a point in 1500 - 2000rpm where the revs would go up and down

I'd jump up to around 2000rpm then go down to almost idling as fast as if i was to press the throttle to 2000rpm and let go and kept doing that

Does anyone know whats wrong with her?

[SuperMazdaKart]

sparkplug leads of course, most likely anyway

[Steampunk]

A loose wire around the ignition harness that is causing an unwanted ground?
When you changed your plugs recently, are you sure you tightened them properly, and connected the leads tightly?
Unplug as many things as you dare, and jiggle some things around.

[TieNN89]

spark plugs were tighten when i put them in altho it was about 9,000ks ago and there iridiums so they should still last

leads were put on tight

ill check the plugs and leads anyway

but shouldn't this happen at any rev? if plugs or leads are the problem or the unwanted ground

its not happening all the time tho when it does it does

[irwin83r]

A loose wire around the ignition harness that is causing an unwanted ground?
When you changed your plugs recently, are you sure you tightened them properly, and connected the leads tightly?
Unplug as many things as you dare, and jiggle some things around.

Dito..

i had a really bad missfire and the car would totaly loose power once hot. i was told plugs and leads and then coil pack! none of which fixed the problem... in the end it turned out to be a loose connection on the cam angle sensor... that must of been working its self loose once the plastic clip warmed up.
so before you buy anything check EVERY thing.... make sure all your plugs in and connected properly, and the connection to the coil pack, check all the connections of your sensors such as cam angle sensor, air flow meter(check its not damaged also as helmundo's one was.. the needle inside had broken... we have no idea how..) check the Crank angle sensor (if possible.. never looked at it myself.. stopped once i found my loose plug )

[TieNN89]

ok checked the the plugs and gave it a clean with a rag even tho nothing came off and made sure it was on tight and the leads

went for a 20km drive and it was like normal

but like i said i didn't always happen it just happens when it happens and then it stops

wheres this plug for the cam angle sensor plug?

[TieNN89]

one thing i know that has been happening is if i drive my car up to 3000 - 3500rpm in the morning while its cold its like a flat spot but once the car is warmed its all good which i'm assuming is normal

[irwin83r]

ok checked the the plugs and gave it a clean with a rag even tho nothing came off and made sure it was on tight and the leads

went for a 20km drive and it was like normal

but like i said i didn't always happen it just happens when it happens and then it stops

wheres this plug for the cam angle sensor plug?

wait till the problem is happening then pull over and have a look ie fiddle with the connections while opening the throttle by hand. the cam angle sensor on the NB8A is at the front of the inlet cam and reads of the cam gear.. on the NAs i think it is off the back of the cam.

[TieNN89]

alright ill have a look at that next time it happens again

[irwin83r]

alright ill have a look at that next time it happens again

any luck?

[TieNN89]

i had a look at the plugs and they seem to be connected etc etc

i was at MX5 Plus yesterday and spoke to Richard about it and he said have a play with the throttle thing so I'll probably take it off and clean it

But the thing is it hasn't happened today nor did it happen when i was on my way home from MX5 Plus but it did happen when i was going to MX5 Plus

It mainly happens when I'm in stop and go traffic

[irwin83r]

i had a look at the plugs and they seem to be connected etc etc

i was at MX5 Plus yesterday and spoke to Richard about it and he said have a play with the throttle thing so I'll probably take it off and clean it

But the thing is it hasn't happened today nor did it happen when i was on my way home from MX5 Plus but it did happen when i was going to MX5 Plus

It mainly happens when I'm in stop and go traffic

not that i encourage reckless driving... but take the car for a good hot drive... to see if its heat related... in stop go traffic the car gets little air through the radiator compared to when its driving under little load on the freeway... my problem seemed to really show its head after a lap or two of wakefield

[TieNN89]

lol tried that doesn't happen

the problem only happens when I'm in those rev range when I'm trying to accelerate slowly

This also happens too Idle rises and drops after sudden stop
http://www.mx5cartalk.com/viewtopic.php ... light=idle

its actually been happening for a month now and now its doing this

Anyway i clean the throttle body now I'm gona take it for a drive

[TieNN89]

went for a half hour drive tonight had no problems what so ever

i had to adjust the idle down tho after the throttle body cleaning the idle went up to approx 1,500rpm so i shorted GND and TEN and adjust it down to 850 to match the idle speed

anyway got a cruise tomorrow well actually today so I'll let you know what happens

hopefully its fixed

[Dweezle]

I know your post was awhile ago, just wondering if cleaning it out did the trick??