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Could someone please give me some ideas to where my power's gone. Car has run great since i bought it 12 months ago, it's a 1.6 na. So i set off this morning and it's like someone stole half the grunt during the night, used to just touch the throttle to take off and now i got to give a good push on the peddle or it feels like it will stall. Up to about 40-50 kays it feels like its struggling but this arvo on the highway doing 100 it feels ok (tested by accelerating up to 130 from 100 and it felt normal).Car has mania intake,extractors and bigger exhaust and timing set at 14* which have all been done by previous owner. Plugs,leads and 02 sensor where done about 6 months ago, please help me, cheers peter.

CAS has moved and changed timing?
Some little beastie has crawled into the intake system partially blocking it?
Induction system leak?

Check the pulley wobble to see if you have the shortnose crank issue??

mid life 5 wrote:Car has mania intake,extractors and bigger exhaust and timing set at 14* which have all been done by previous owner. Plugs,leads and 02 sensor where done about 6 months ago...

Anything else done - such as a cam belt?

Sounds like a blocked CAT to me.
Do a search on miatanet for blocked CATs and see if the symptoms are the same as yours.

Blocked Cat/muffler/hot dog?
Blocked air inlet or filter?
Dragging brake caliper?
Handbrake stuck on?
Valve timing slipped? ---> loose timing belt or slipping timing belt pulley on crank
Ignition timing slipped? ---> loose CAS bolt or slipping boss on crank
AFM faulty?

The list goes on ....

Ok, thanks for the suggestions, timing belt was done less than 10 000 kays ago so should be good. Today i replaced the fuel filter, spark plugs, cleaned air filter and changed oil & filter, still doing it. Checked the cat and muffler by tapping with a rubber mallet, no rattles or weired noises plus the exhaust note is the same as when it was running fine. While i was cleaning the air filter (mania cai) i thought i try it with no filter on and the engine revved a lot smoother (no missing) so i tested it on the street but still took of from a standing start like a snail, and thats with accelerator flat (did the same with air filter on). But when i went to reverse back in the driveway it went fine, like theres nothing wrong with it, any more help, cheers peter.
ps Does any one no a good mechanic near ipswich i could take it too, prefer someone with mx knowledge.

mid life 5 wrote:...timing belt was done less than 10 000 kays ago...took of from a standing start like a snail...

I reckon you've got a wobbly crank. Your timing belt change is the culprit. The mechanic who did it has caused (by not re-installing the key properly with a new bolt torqued to the correct spec) a failure of the pulley keyway causing your timing to be funny (no power).

Look at the crank pulley in the engine bay when the car is idling. If it wobbles, take the car to MX5 Plus Service and get them to put a new engine in for you...

Boags

Yep, it's starting to sound suspiciously like a stuffed crankshaft pulley keyway.

JBT wrote:Yep, it's starting to sound suspiciously like a stuffed crankshaft pulley keyway.

And NOT like an empty fuel tank.

Boags wrote:

JBT wrote:Yep, it's starting to sound suspiciously like a stuffed crankshaft pulley keyway.

And NOT like an empty fuel tank.

*SNORT*

bugger, snotted on me keyboard

Hasn't Boags got a spare motor from his lack of fuel escapade?

bruce wrote:Hasn't Boags got a spare motor from his lack of fuel escapade?

Nope.

How wobbly is the wobbly crank syndrome, mine moves slighty by a mm or two, cheers peter.

mid life 5 wrote:How wobbly is the wobbly crank syndrome, mine moves slighty by a mm or two, cheers peter.

I will be in Ipswich over the weekend and can have a look if you like..