Lumpy tickover (cabin shakes),
Feeling of pulsing between 2500-3000rpm (engine feels like it's trying to accelerate and decelerate at the same time),
Very slight hesitation under hard acceleration,
Loss of acceleration at 4000rpm (happened twice in a month, but 3 times inside 5 minutes on the way home last night)
And a general feeling of loss of performance (although this could just be because of the concern caused by the other symptoms)

Urgent views needed because the fun has gone from Scooby ownership at the moment, and been replaced by worry.

 

Im defo no expert, but learning all the time, could be Lambda Sensor gone, or Maf gone

You could connect up the balck connectors under the dash, and turn the ignition on (not starting the engine) and watch the Check Engine Light for pulses, then check this site for error codes

http://www.saxonfields.freeserve.co....ding_ECU_Codes

Steve

 

Blocked air filter maybe???

 

Depends on the MY, but my guess would be MAF because of the acceleration problems. It's possible the car's running lean enough that it's detting so the ECU drops boost right back (7psi ish) hence pants performace, or if it's reset (ignition cycle should do it) the first acceleration run you may get very good acceleration as it's running lean but at full boost - and detting - meaning it then drops the boost again & then you're back to slow.

I wouldn't bother about the CEL thing myself - unless the MAFs completely gone (rather than misreading) it won't read as a fault. With no instrumentation, I think the check to do is disconnection the MAF with the car at idle & see if it gets better, in which case the MAF is misreading (although I'm not positive about this test!).

 

Thanks for replies.
Car is in to the dealer on Thu, let's just hope they can find the fault.

BTW. Cambelt change recently - would incorrect timing set up have the same effect?

 

My timing was out on my93 a while back and i was having all the same problems as you...

So yep it could be the timing, also have you checked your spark plugs...

HTH,

G.

 

Maybe light at the end of the tunnel.

Thanks Greeno.
The plugs were probably checked on the last service (though I'll check).

With a cambelt change am I right in thinking the timing would be adjusted? I'm afraid I'm a complete know nothing on the mysteries under the bonnet.

 

Just to add a dab of uncertainty - virtually no dealers can check whether the MAF is functioning correctly or not - they only have access to the 'select monitor' which can't tell.
So it'd be handy if it was the timing, then

 

My car was like this, new set of plugs sorted it out. The ones that came out had only been in for 12000 miles, or so said the history. I expected them to last longer, but don't know if they were really changed last time because it was before I owned it.

 

Yes my car is doing this also but only when it is cold, I know that it is due to plugs, not looking forward to changing them.

I would think that your problem could be spark plugs as suggested

 

Yeah Plugs arnt the most fun thing to change on the scoobs...

It took me 2 hours to fit mine....

G.

 

I have found that cleaning and regapping the plugs every 7,500 miles does miracles.
It seems to help acceleration, lumpy idling and poor gear changes.
I know its a PITA job but it really is worth it.
I tend to find the back two cylinders tend to get coked up more especially no.3? Anynone know why?

Nick