1998volvo s70 idles rough acceleration is fine

What is the problem with your emergency brake?

If it is the shoes, you just need to remove the rear brake rotor to access the e-brake shoes. If it is the cable that needs adjusting, you can access it by removing the center console.

could be either a coil pack not working properly, or mass air flow sensor, or could also be the throttle body. its elctronic

Could be, but you will need to check for trouble codes, since the engine light came on. The code or codes may help you troubleshoot it.

could be vacumm leaks,or MAF needs replacing.Wire should be fine,unless its biodegradable

Rough Running Engine - James on Engines #2 - Bell Performance

https://www.bellperformance.com/blog/rough-running-engine

Apr 21, 2015 - When diagnosing an engine with a rough idle, there are certain things that must be ... If the problem does not reoccur, the codes will be erased by the computer. ... when accelerating the vehicle, which causes a higher fuel demand. .... it was water in gas...added added Gas LineAntifreeze/Water Remover.

Ckeck your govenator .

You might need to change the fuel filter, Check your air filter also.

try this b4 taking things apart... redexe/wynns fuel additive and using high octane fuel the computer will adjust running accordingly...

It sounds like you may have a problem feeding the fuel to your engine, I had the same problem with my 89 RS. All the 1989 model's fuel systems were recalled. I think you may need a new fuel pump. The fuel pump is located inside the gas tank in the rear of the car right under the rear axle. The fuel pump itself isn't too expensive, but with other small parts such as the electrical harness upgrade and fuel filter and the labor you should be looking somewhere in the $500 range. I hope this helps.

Sounds like fuel starvation. Would suggest cleaning any filters in the fuel line or replacing.
Also check the stop idle valve. This should be inline in the air intake pipe to the intake manifold..
Remove it and clean with WD40.Make sure you note the orientation of the spring.
To reset the ECU disconnect the battery for 5 minute the reconnect. The ECU should reset to factory settings. Make sure you know radio and alarm codes!
Try petrol additive STP or Redex to clean inside the engine.
Thats as far as my knowledge goes, hope it helps.