MX3 1.8 V6 Kangarooing Problem

ShellyD · Post by **ShellyD** » November 20th, 2007, 7:55 am

I bought a 98 V6 a few weeks ago and it's started kangarooing really badly, to the point I have now renamed it Skippy.

Once the engine is warm it ticks over at 1000, then drops to about 600 and then revs up and down between 600 and up to 650. Then when you go to pull away there's no reponse there and then it kangaroos down the road until you get up to 3rd gear and about 20+ miles an hour. The only way I can mildly control it is be getting the clutch to biting point and then putting the accelerator down until it eventually responds, but still judders a bit. It's not only embarrassing but pretty dangerous, as pulling out of a junction it can just cut out half way in the road. It also conked out on a hill the other day and I only just managed to get up the hill by revving the nuts out of it.

The car had a full service about 120 miles before I go it, so I would assume plugs, filters etc have been changed. But I'll have a look through my paperwork and check that is the case.

Anyone have any ideas what this is and what sort of cost it's likely to be?

Many Thanks

somorecords · Post by **somorecords** » November 20th, 2007, 8:27 am

my 92 gs has this same problem, however it only does it occassionaly. the best guess i have came to is that i think my MAF (or VAF whatever, the damn air intake part lol) is sticking, the cylinder in the middle was sticking slightly when i spliced it into the new intake but i thought it would straiten itself out, but i guess it hasnt so i was going to take it off today and loosen it up, if it works i will let you know. if it doesent i will go back to the drawing board

tehbrookzorz · Post by **tehbrookzorz** » November 20th, 2007, 2:55 pm

Resolve vacuum leaks, reset IAC in diagnostic mode, stop driving over Kangaroos.

Raven95150 · Post by **Raven95150** » November 21st, 2007, 12:50 am

Make sure your intake tube is fastened securely at both ends. Mine was doing pretty much the same thing, I was like what the @#$%&....Finally I noticed the intake tube was coming off. I put it back on and tightened the clamps and that fixed it.

somorecords · Post by **somorecords** » November 21st, 2007, 12:54 am

my cousin thinks the problem with mine is the "throttle positioning sensor" or something along those lines, personaly im used to working on carbreuated V8s so all these damn sensors and things are somewhat beyond me but i would suggest checking it out becouse it sounds like you have the same problem as me, and i still havent got to checking my MAF

ShellyD · Post by **ShellyD** » November 21st, 2007, 4:30 am

Thanks for your responses. I'll check out the air intake etc and see if there is anything wrong there. When I get to the bottom of it I'll let you know as it could help someone else.

ShellyD · Post by **ShellyD** » November 21st, 2007, 10:01 am

Just to update and close this off. It turned out to be a large split in the air intake duct. Has been taped up for now and runs lovely again. Thanks for the advice

PurpleDinosaur · Post by **PurpleDinosaur** » November 21st, 2007, 12:55 pm

I'm having the same problem... it either bucks like a bornco or I have to launch so hard that I get wheel hop...

Just posting because I' grateful that this post "just happened" to be at the top ... I was anticipating a lengthy search session...

hgallegos915 · Post by **hgallegos915** » November 21st, 2007, 1:57 pm

I notice we most seem to have this problem in winter.. couild be the iac or a bad tps. I think i fixed mine by leaning the fuel mixture and resetting the tps.

I assume its the tps or iac.

can be vac leak tho.

The iac can be removed to clean any deposits it has inside. Mine had alot of crap in there.

cabriolet · Post by **cabriolet** » November 26th, 2007, 5:28 pm

I have the same problem, it was really bad, kangarooing stuck in traffic

Pcv hose loose clamps tightened that up worked fine for a while
happens at odd times but way more less severe

dubspeed · Post by **dubspeed** » November 27th, 2007, 11:20 am

Does the car die out on you at all, or does it just kick? If it starts dying out of the blue, that could be the IGNITOR...Seems that fix can get expensive...Hope this helps

cabriolet · Post by **cabriolet** » November 27th, 2007, 11:30 am

no it doesnt die out
and it happens alot less now
but the car feels like....something's holding it back....bad throttle response,and at the same time the brake and clutch doesnt feel as good either when it happens

PurpleDinosaur · Post by **PurpleDinosaur** » December 5th, 2007, 10:54 pm

My problem was the intake boot... makes sense. MAF sensor tells ecu less air is coming in (because its coming thru the cracks in the boot), ecu backs off the fuel to adjust but theres plenty of Air (from the cracks) therefore the car runs super lean and bucks... at WOT the issue goes away cause the ecu is not doing its thing.

also makes sense that the problem is more sever in the winter since the air is denser which would make the leaning out issue worse.

Check the boot carefully... cracks like to hide on the underside.

Also - in the winter the boot is more brittle making it more likely crack.

just sayin'...

course my ride died after the boot fix and I have no clue now but thats a different issue.

wytbishop · Post by **wytbishop** » December 6th, 2007, 12:53 am

PurpleDinosaur wrote:My problem was the intake boot... makes sense. MAF sensor tells ecu less air is coming in (because its coming thru the cracks in the boot), ecu backs off the fuel to adjust but theres plenty of Air (from the cracks) therefore the car runs super lean and bucks... at WOT the issue goes away cause the ecu is not doing its thing.

Actually, the VAF tells the computer exactly how much air is entering the engine...through the VAF. The problem is that a bunch of air is entering after the VAF. This is the dreaded "unmetered air". So the ECU is not backing off the fuel, it's just delivering the correct amount of fuel for the amount of "metered" air but it doesn't know about the sneaky unmetered air. The end result is a lean mixture, but I'm all about accurate information.

just sayin...

PurpleDinosaur · Post by **PurpleDinosaur** » December 6th, 2007, 4:43 pm

wytbishop wrote:
PurpleDinosaur wrote:My problem was the intake boot... makes sense. MAF sensor tells ecu less air is coming in (because its coming thru the cracks in the boot), ecu backs off the fuel to adjust but theres plenty of Air (from the cracks) therefore the car runs super lean and bucks... at WOT the issue goes away cause the ecu is not doing its thing.
Actually, the VAF tells the computer exactly how much air is entering the engine...through the VAF. The problem is that a bunch of air is entering after the VAF. This is the dreaded "unmetered air". So the ECU is not backing off the fuel, it's just delivering the correct amount of fuel for the amount of "metered" air but it doesn't know about the sneaky unmetered air. The end result is a lean mixture, but I'm all about accurate information.

just sayin...

jeebus - split hairs much?

but ya did get me on the corect designation being VAF vs MAF so props 2 u.

MX-3.com

MX3 1.8 V6 Kangarooing Problem

MX3 1.8 V6 Kangarooing Problem

me too...

ignitor