been suffering intermittent hesitation on my my99 the last few months. seems to have co-incided with maf replacement and ecu reset but not convinced its related.

would be once maybe twice a week. just had the car serviced by my regular dealer, advised them of the problem and told them to change the plugs. car is now 10 times worse to the point where its dangerous to drive - just cant rely on it to go!

i'm assuming the plugs are right and gapped correctly (never heard a bad word about my dealer and always been excellent service), so would this indicate a problem with the leads ?

if it were you, what would you do ? replace the leads and see how it went or go back to dealer for them to diagnose it further ?

any advice welcome.

Hi there
Please explain what you mean by intermittent hesitation cause i think my99 might be doing the same thing, but only when cold.

mick

mick, its like a misfire but not to the point where it is actually mis-firing. you put your foot down and it jumps about, without going forward. change down a gear or dip the cluth and rev it and its fine until the next time. if that makes sense...

anyone ?

U could try the wastegate control unit on the inner drivers side wing.

I would check the plugs, leads & plug packs

soobmeister, if thats the same thing as the boost control solenoid under the alarm bracket, i've already cleaned that with brake caliper cleaner to no avail.

is there some way a subaru mechanic can hook up a laptop or something and have me take the car for a spin and have a look at the data to help pinpoint a cause ? does such a technique exist ? if so, would all dealers be able to do this ?

anyone have an idea of the price of a set of plug leads ?

cheers

That is the same as what mines doing... Someone out there must know what to do!!!!!!!!!!

At a rough guess you could try the coil pack, this can be a problem, or new HT leads.
Do you have any modifications on your car?

Tony

Mines standed as far as i know, only had it a couple of months.


Mick

have you checked for leaks from pipework???

you say you have replaced the MAF, was it a new one???

does it idle ok???

do you have any fault codes???



[Edited by jonny gav - 10/25/2003 6:28:28 PM]

what air filter are you using???

completely bog standard my99, no mods, idles fine after the maf replacement (new maf, not second hand).

no fault codes. dealer confirmed this and cleared the memory.

i've had this kinda problem twice before on previous cars :-
rover 220gti - loose plug cap
mk3 escort - carbon plug leads broken down, replaced with copper ones

i'm presumin that the plug leads were dodgy and by movin them to replace the plugs has knacked them completely. does anyone know if they are carbon or copper core ?

does the ecu record misfires and the cylinder if the CEL doesnt come on ?

all help appreciated

mick, i'm back at dealer first thing monday mornin. no courtesy car available at this short notice so i'll be stayin with car there til its sorted. i'll let yer know how i get on.

strongly suspecting plug leads. was before but expected it to be just the same after the new plugs since it seemed to be worse when wet which again pointed to leads in my experience.

jonny gav - car was serviced so would have hoped they would spot leaks from pipes. i havent seen any, but wouldnt have been lookin for that. can you be a bit more specific - which pipes ?

cheers

[Edited by Riftzone - 10/25/2003 9:27:09 PM]

Cheers Riftzone... Hope its nothing to bad

i was thinking of the pipes that go to the map sensor/ boost control solinoid but if it was leaking from there you would have a fault code.

have you took out the crank position sensor and cleaned it???

cheers jonny, i'll have a double check of those pipes. crank sensor you say ? no idea what/where so i'll have a search.

would you believe it, the damn thing is drivin superb today ! feels much more responsive since the new plugs. hmmmm....

crank position sensor is directly under the alternator, its redish brown with a 10mm bolt holding it in.

take it out and give it a clean, its an easy job ;)

£114 and a new set of plug leads later and hopefully thats that.

had a chat with one of the mechanics and in a my99, they've never seen an igniter/coil pack unit go. hesitation has always been down to plugs, leads or maf. with all 3 done, hopefully i wont be getting any more hesitation.

being worse in damp weather and generally intermittent points to leads.

they've never seen another sensor cause a hesitation problem where the sensor hasnt failed completely, apparently.

certainly got some hesitation on the way to the garage and none on the way back. fingers crossed...

nope, plug leads didnt help. dealer suspecting maf sensor which i fitted back in august to have been faulty and will replace this free of charge. so with new maf, plugs and leads, if it still does it, what next ? :(

seriously bugging me now.... :(

[edited to say car is now as if was before it went for the service, not the un-driveable dangerous beast it was after the service, so plug leads have helped in that respect]

[Edited by Riftzone - 11/11/2003 7:46:03 AM]

Hi There...
My99 is going for its service on Friday and they are going to have a look at the same problem.But since i have started going to the same petrol station and filling up with optimax it seems a lot better, not done it for a week now so fingers crossed.

v interesting mick. will try some if it persists after this last maf and tinker session on thursday.

did you find it made a difference instantly or did it take a few tanks ? had your car been fine previously on normal unleaded (like mine has) ?

cheers.

I had been using diferent fuel all the time but after about two tanks of optimax you could feel it getting better.... Just make show you run it as empty as you can first. It didnt like it at first, if anything made it worse, but a couple of blasts down the bypass sorted that.

Mick

top

nope. new maf hasnt solved it. so new plugs, leads, second maf and hesitation still there.

the mechanic showed me a subaru bulletin. the bottom line of it was that hesitation is a characteristic of my99 and my00 cars, not a fault. he also said that in their training, they recommend optimax for uk cars.

oh well, optimax here i come...

Try unplugging the O2 sensor and see if this makes any difference.
FC