Can anyone help with this problem? Car is NA, manual with Blitz cans.

 

Just been in France for past week, car was running fine until late Monday night.

 

Just paid at toll and accelerated away through 1,2 & 3 to avoid other cars, then got up to cruising speed, about 90 mph, not long after problems started.

 

When I release throttle just a fraction, the noise from exhausts was very loud and bad vibration, release throttle totally noise stopped, accelerate and hold at cruising speed ok - just when I released a fraction.

Then problem cured itself a flittle while down road.

 

Next few days and coming back to UK struggling when accelerating in wrong gear (feels like handbrake on, but not), struggling up hills and when release throttle lots of popping in exhaust - unburnt fuel I think igniting in ehaust. Now think missing on 1 pot.

 

What am I looking for as problems - got new plugs to put in (when rain stops) - how do I test coil pack etc?

 

Cheers Rob

Sounds like exhaust manifold broken somewhere, leading to lotsa noise and an airleak which causes the backfiring.

dont think its manifold, noise loud noises on idle - sounds fine - loud noise hasnt happened for past couple of days but misfire has - car runs ok up to 3k then misfire starts but not all the time

sorry no loud noises on idle, manifold ok

In that case it could be a loose coilpack connection, which will also lead to fuel igniting in the exhaust.

 

With the engine ticking over go round and disconnect each in turn to identify which one is giving problems.

 

There is also an easy way to check whether the engine is running on 5 or 6 cylinders, rest your hand on the door sill, if there is uneven vibration it's not running on 6.

its the maf sensor, the exact same thing happened to me on a 94 impreza wrx, it was struggling uphill to a point that i was in first gear and at a near stop revving like **** (not fun!) and the exhaust became extreamly loud like you say.

 

My guess is the MAF

p.s. did u know the maf is the same size on a early impreza wrx as the zed only with a red label

2 things - recently added a new induction kit - which increased the size of the cone to 4 inch, but ran ok for 4 weeks - just changed plugs, they look good, just right combustion

BUT plugs I took out were BCPR6E - 11 which are not platinum - put in PFR6B-11 now but doesnt seem to have cured

will other plugs cause problem?

still could be the maf, it only takes a little contaniment on the metal wire sensor for it to go all faulty,

Im aware that the Z32 Maf makes a good upgrade for alot of scoobies for reliability and apparently a size increase but it only takes a little.

 

On the scooby you could check if it was this that was faulty by unplugging the wire clip with the engine running, if it cuts out then the MAF works, if it carries on running its faulty.

 

Not sure if this will help but its worth asking someone in the know.

you could also try cleaning the wire with brake cleaner and i tiny brush but dont be too rough

Check for ECU error codes, that will tell you if there is a MAF problem. Also, if the MAF is faulty then you should be limited to 2400rpm.

cant see it being MAF, revs to limit - not running rich or lean

 

just wondering if the incorrect plugs caused a problem or have a sticking valve

Have you tried a compression test?