1998 Saab 93..... Talk to me

If the two new tyres are on the front,try swapping with the back set. I have had cars with budget tyres, and it can have quite an effect on the way the car handles. Especially if it's something with a bit of weight like a Saab.

Gravel drive? Definitely not, its parked on a rough council estate in Birmingham!! The wobble just seems to go away after a few miles driving so i can see your logic.

As for the fuel issue theres no leaks and I'm getting around the same mileage on every fill up - which is very often!!!

Hmmm... if the idle is showing correct, my guess would be the issue is over-enrichment on acceleration. I wonder if the MAP sensor is iffy, showing greater pressure under boost than is actually there, causing overfuelling. That would be in open loop so the lambda wouldn't adjust the mix?

Unless, of course, the idle isn't closed loop but a static map and the lambda is indeed buggered

As for steering wobble... something slack which warms and expands (and thus tightens, reducing slack) with friction? Bearings? Ball joints, perhaps?

Just for comparison, I used Avon ZZ3's on my '99 2.0 HOT. Never had the Abbott kit and never really suffered any untoward wear or wobble. I used to get mid to late 20's MPG and never hung around. Having said that, my 3.0 v6 X-Type auto used to return around 18mpg. Is the offending vehicle auto or manual?

Ok just an update on things.

Its an automatic with a b204e with the red cassette (already been changed) and runs very smoothly. There are no management lights on the dash and the sid display works perfectly (yes i know!!). I havent really looked at the maf sensor being an issue as no eml light on.??

Just to put into perspective, i put 30 quids worth of fuel in and return around 100 miles. This is driving round town with minimal stop start traffic.

As for karl at noob tune.... Where is he based? I wouldnt mind having it remapped/looked at to be honest.

Karl did a great job on my Aero HOT and helped me sort a couple of little issues the car had when I brought it to him Hes not far up the M1

To check the bulkhead, get someone to steer from lock to lock while the car is stationary. Meanwhile watch the bulkhead around the drivers side area sort of around the brake servo, thats where mine had started to crack.

That mpg sounds a bit on the low side to be purely as a result of city driving to me? My car never gets near going below 20 even with a heavy right foot. (Albeit mine is a manual and the B205 engine which is supposed to be a bit more economical)

Did the plugs tell you anything when you changed them? Any chance the car is running very rich?

Ah yes you're right, forgot the OP's car is T5

reset SID and see what happens - the unit is reliable, unfortunately the inputs it uses for displaying the data aren't always ! can't remember if this tank has an upper baffle - if it has, this as a notorious source of improbable fuel shenanigans (but i think this is just the 9-5's)

is the boost behaving normally? a collapsed cat will impair mpg and shows up as low boost etc.

temp coolant sensor worth considering - there are 2, one talks to the ECU and the other informs the gauge. an open SID (Jules can fix this for you) would let you see what coolant temp the ECU is actually seeing. faulty data could give rise to overfuelling as the ECU stays in coldstart cycle.

could be a lambda staying in closed loop and holding control of the fuelling. in open loop the maps take over with no compensation from the lambda. the "wrong" lambda will screw the fuelling as the voltage expected by the ECU will be outside the parameters it's looking for. i can't recall my T5's but on T7 the upstream sensor does the hard work with fuel trimming so test him first. Trionic is very particular about what sensors it communicates properly with and Lambda faults don't always give you the EML so T5 self-test no good here I'm afraid

i have seen a MAF incorrectly fitted which gave some very chin-stroking figures on SID

every saab i've ever had has been very sensitive to tyre choice - distinct shimmy with some brands and not with others. are your budgets "high load"? - they should be. budgets do work OK on Sabbs though, on the 9-5 i currently have a set of BCT (just liked the tread pattern !!) and they've been great. the 9-3 is pants on avons but fine on conti's - go figure !! check lower arms again - these can often pass an inspection whilst signalling their gradual deterioration at the same time. i used to buy the premium brands but found that it's more cost effective to use the cheapest i can find and treat as a service item.

you can easily check for bulkhead cracking yourself (it's not actually a crack - it's a weld that unpicks itself) by sitting in it and swinging the wheel around. movement of the pedals would be the worry.

strut top mounts worth a look, especially as wobbling is more pronounced on bumps. all cheap and easy fixes, rack and subframe braces will help enormously on a 'vert (which, frankly, are renowned for being wobblier than a champion wobbly thing from wobble town)

thinking tangentially - wheel wobble and poor gas mileage? are the brakes OK?

start cheap though - check plugs (make sure you have the correct spec, it's for a reason), air filter etc.

paul

air leak on the inlet side?

lift the plastic cover over the TB and see if there's anything obviously amiss with cabling etc.

idle control valve gummed up ?

again, possibly coolant temp sensor playing up ?

TB's are known to have issues relating to the readings received by the ECU being outside the tables - the electronics get manky after a few years and the readings become variable. It's an easy replacement but would have expected a CEL and a "performance related problem" to be showing up if the TB had discrete problems.

paul