1994-2002 [Subscribe to Daily Digest] |
Hey all,
I don’t post often, because I usually find my answers via search, but I currently have a problem that I'd like input on.
The car is a ’97 900 SETC, MT, 135K w/ minor mods. I’ve owned it for 5 years.
Over the last month or so, it began periodically going into serious misfire episodes under load, but has never latched the CEL. Misfire at idle or light throttle (cruise control on the highway for example) is barely noticeable, but under load (maybe 1/2 throttle on up) it’s so severe I have to slip the clutch when taking off from a stop, otherwise it will buck pretty badly. It hasn’t stranded me, but certainly feels close to doing so. At first I thought it was bad gas, but I’ve been through at least four tanks of super from different stations and one Techron treatment, so I ruled that out.
I accidentally made a discovery a few days ago. A cold front came through, so I switched to econ mode to try and save some gas and the misfire episodes ended. I switched back to auto mode today to test my theory and I did have a misfire episode, but a later drive proved to be normal…no consistency is killing me. The AC compressor has always been pretty noisy while engaged, but I thought I’d check the serpentine belt for abnormal wear, just in case it was binding occasionally and causing slippage, but everything looked fine (btw, I run the short belt setup and the belt, upper idler pulley and tensioner were replaced about 10K ago).
Also, I don’t know if this is related, but on two occasions recently, the car stalled almost immediately after a cold start…this has never occurred in the past. It finally started up on the third or fourth try. However, a week has gone by without a recurrence.
Potentially related items I’ve replaced are as follows: Plugs (NGK7s) replaced two days ago (normal deposits, but changed anyway); PCV check valve replaced under 10K ago; Battery replaced under 20K ago; DIC replaced (new red) under 25K ago; IAC and TB were cleaned about 35K ago; Vacuum lines converted to silicone (large line to purge valve included) about 35K ago (checked them two days ago and all were fine); Techron Concentrate every 10-15K or so
I’ll continue to eliminate variables, but in the interim, if anyone has diagnosed a problem that caused similar symptoms, I’d really appreciate their input.
Thanks in advance.
Paul
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.