98 s70 t5 hiccup

Post by **318mike** » 12 Jun 2013, 08:43

I recently bought a 98 s70 t5 with 158k.It runs great,but when the ambient temp outside drops below 60 degrees I get a hiccup,mostly when I'm sitting at a stop light,an occasionally on acceleration.It doesn't do it when the outside temp is warmer(just when it drops below 60).No check engine light or codes.I do have an intermittent ABS and tracs light,but I'm pretty sure its the abs module.Thanks in advance.

Post by **jblackburn** » 12 Jun 2013, 16:19

I'd clean the MAF and connector and see if it goes away. Not a whole lot to go on without codes/other symptons.

Any service records? A tune-up wouldn't hurt (plugs, cap, rotor, air filter, wires, etc) if you have no idea when it was last done.

Post by **318mike** » 13 Jun 2013, 05:43

Thanks JB...No service records,unfortunately.The car looks and runs great.I think I got a good deal at 1300.I had to change the timing belt,pulleys, and water pump because they had over 100k on them.When I test drove the car everything seemed good it was a warm day 70+.The next day it was in the 50's and it would hiccup when I came to a stop for a couple of minutes or so.Thought maybe it had some bad gas or something,the person I bought it from said it had been sitting for a couple of months.The hiccup seemed to stop,but the weather had also been at least 75+ for a week or so.Then yesterday it dropped down to the 50's and the hiccup returned.I'll take your advice and clean the maf and do a tuneup.

Post by **jblackburn** » 13 Jun 2013, 05:58

Hmm...try one other thing. There's a vacuum line from the purge valve into the intake manifold. Next time it's cool again, take it off and tape both ends up. See if the stutter is still there.

Post by **318mike** » 13 Jun 2013, 19:17

Where's the purge valve?

Post by **jblackburn** » 13 Jun 2013, 21:16

Radiator shroud, just in front of the battery. It should have 3 lines hooked into it - may be either a circular valve or a rectangular one.

Post by **E Showell** » 14 Jun 2013, 14:33

I've had this hiccup for some time. Not cured by an engine swap (but that wasn't the reason the engine was swapped). I don't think it is vacuum-related and it doesn't throw any codes, but it is both annoying and elusive. It is as Mike reports, but I did not notice it to be temperature sensitive. After the engine is warm and I stop at a stoplight, I get a momentary idle dip by c. 100-150 rpm than it comes right back up to about 850. I'm think it might be some kind of sensor or software issue.

Post by **abscate** » 14 Jun 2013, 16:01

Purge valve on my 1999, hides under the air cleaner feed hose..

dont forget to check your part number against the brand new one I have for sale in PARTS FORUM if you need one..

Post by **318mike** » 15 Jun 2013, 09:46

Its temp sensitive and now it doesn't do it.The outside temp is 75+ today and no hiccup,but I know that once the ambient on my dash reads 60 or less "hiccup".Its probably why the guy sold it to me so reasonable,its really a nice car and I fixed the abs module yesterday.Replaced it with a JY one that I got for 30 bucks(sorry sponsors money is tight).I know that it was a rebuilt one because it was obviously opened and it had a number engraved on it 39647,maybe one of matty moo's.I took it off what looked like a nice 98 s70 t5 that had a telephone pole imprint on the front bumper,grill and hood(tragic end for a nice car)....thanks for the input everyone

Post by **318mike** » 17 Jun 2013, 19:17

The hiccup is no longer temp sensitive,it did it when the outside temp was 80+.The one constant seems to be when sitting at a light for more than a couple of minutes it will hiccup everytime.Other than that its random.A tuneup seemed to make no difference.I read that E Showell has the same problem even after changing the engine which tells me that its something that remained in the car even after an engine swap.Maybe an oxygen sensor or something that wouldn't be changed out with an engine swap...any thoughts?