The wife's 99 S70 GLT with 88k miles suddenly started skipping. She drove it to work, about 12 miles, no problems. Came out at lunch and skipping so bad she could not pull out of parking spot.

I went later in the day and drove it to a friends shop. Skipping/missing bad. Pressing accelerator would only get 2500 rpm max. I could release the accelerator and feel the transmission shift into the next gear, but still no more than 2500 RPM max.

At friends shop, tried to connect tester but would not read Volvo OBD II.

Let the car sit for an hour, cranked it back up and it ran fine. No skipping/missing. Revs as normal. Drove home and tested at 80mph with no problems.

Next day, cranks and runs fine. Then starts skipping again after several short trips where car was started and stopped.

No lights are own in the dash.

2 questions. 1. Recommendation for tool to read OBD II codes (pc based if possible).
2. What in the world could be causing this intermittent problem?

Thanks in advance for any and all help.

 

When was the last tune-up? I would start with the basics.........

Plugs
Wires
Cap
Rotor
Air/Fuel filter

A generic OBDII reader can read engine codes if the person knows how. I have a $70.00 reader and it works under "generic OBD II" settings.

 

thanks for the ideas.

Last tune up was dealer performed at 70K miles.

 

One or more of the coil packs might be bad.

 

Thanks for the input but this is a 2K tester not a game boy version. Requires a different module for different car brands. It will check transmission operation and other components of the car. The reader would not communicate with the volvo. But I have orderd a module and will hopefully know.

 

I have determined the skip in the 99 S70 only occurs after the engine has been run at full operating temperature. Cranking the car and driving first thing in the morning and no skip or miss. A short 10 mile trip and restart the car and the skip/miss is back. Continue to turn off and re crank the car and the engine will eventually start and run normal.

My question is WHY would no codes be registered in ODBII when this thing is missing so bad it can barely run? Also the check engine light is not on.

I have not yet made any changes or repairs as I would like to determine the EXACT problem instead of just throwing parts at a fix.

I know this is one of those almost impossible problems to find/fix. I am looking for possibilities. If it was a plug, plug wire or a coil pack it seems it would do all the time when the engine was warm.

Has anyone ever seen a problem like this associated with a fuel pump?

Thanks in advance for any and all help.

 

Hook a fuel pressure gauge to the engine and tape it to the windshield so you can see it while driving. If you see pressure drops when it acts up then you know it's a fuel delivery issue.

 

Maybe ETM is bad. It will not always throw a check engine light.

 

it was the ETM (electronic throttle module). The dealer replaced it under warranty. Thanks for all the answers.

 

WHat you're ecxperiencing sounds like what's happening to me! S70 chokes/bucks/nearly stalls once in a while, but normally is perfectly AOK. Could you tell me about this ETM, and warranty? TIA / Pat

red_71_KG@hotmail.com

 

i took the car in to the local Volvo dealership expecting to pay the full price. I was told that a recall or TSB was issued on the Electronic Throttle Module (ETM) several years ago. I checked my records and notice the prior dealership had "updated" the ETM software. Since it had occurred again the only option was to replace. It is covered to 100K miles I was told.

The symptoms were: crank up and it would shut down. Then crank up and run fine. It finally would not run. Seemed to be only running at idle when the last problem occured. With the throttle pressed to the floor it would only run about 20 or 25 miles per hour. It would not accelerate but did not seem to be skipping. I drove it about 10 or 12 miles to a friends shop. Turned it off for about an hour and then restarted. It cranked and ran fine. I did notice that the cruise control would not work when I drove it to the shop. not sure if this was an electrical issue or the ETM.

Hope this helps.