2000 S70 stuttering/jerking when at low RPM

Gatekeeper21 · Post by **Gatekeeper21** » 30 Jun 2011, 14:14

I really have no idea what is going on and I am hoping someone can point me in the right direction. First I will note that this is a manual transmission so that the following makes sense. When I slow down a bit too much for a gear, but sometimes don't have a chance to downshift (1500 ~ 2000 rpm range), the car jolts once or twice when I am speeding up. It is not right when I accelerate though, it doesn't jolt until I have already started speeding up a bit. If I am very light on the gas, it doesn't happen often...but when I accelerate hard, it always jolts. It does this in second and third gears...haven't really noticed it in other gears. It has not done this in the last 11 years, so I know it is something new. Also, if I don't give it enough gas when starting into first gear, I sometimes get the same jolt...so i have to rev the engine a bit when starting off to prevent it from happening. Also, it is not throwing any check engine codes

My thoughts of possible problems are:
ETM/throttle body/MAF/oxygen sensor
Air filter (it is dirty and needs to be replaced, but I am not sure if it would really cause this)
Spark plugs/wires/distributor cap/ignition coil
fuel filter or fuel injectors
clutch slipping
cylinder misfire

I have already cleaned the throttle body, but that did not seem to make a notable difference. I wish I could say I keep up with replacing everything on time, but I don't have the money right now to spend unless it is a necessity. Thanks for any input!

Post by **JRL** » 30 Jun 2011, 14:44

Learn your car
You do not have plug wires, you have 5 coil packs
I would lean towards
ETM
MAF
Bad or cracking coil(s) and check everything else you mentioned except clutch, that's not a clutch symptom
MILEAGE always helps when you ask a question

Post by **JRL** » 30 Jun 2011, 15:25

I forgot
Add possible dirty fuel filter
Fuel pump issue

Post by **matthew1** » 30 Jun 2011, 15:34

If your spark plugs have more than 15k miles on them I'd put OEM Volvo plugs in, and for sure a new air filter. Run some fuel system cleaner in it next fill up. Do the simple things first.

Gatekeeper21 · Post by **Gatekeeper21** » 01 Jul 2011, 10:26

Thanks for the info, glad to hear that it is not clutch related. Wasn't sure about the wires...when i looked online, i found a site that supposedly sold ignition wires for the s70, so i thought they were separate parts (obviously wrong info there). I took the air filter out yesterday and drove it around the neighborhood, but it didn't make a difference. Is there any way to test the MAF or ETM since the check engine light hasn't come on? Can I clean them in any way? Also, it is currently around 190k miles

It has been quite a while since i have replaced the spark plugs, so i will go ahead and do that and check the coils. If that doesn't seem to make a difference, i will run some fuel cleaner through the system