Hello, i have a 1998 volvo s70 t5M with a misfire. All parts replaced/modifications listed below and have been installed within 2k miles ! Codes for check engine are

P0300

P0301

P0302

P0303

P0304

P0102 (maf was unplugged)

P0340 (checked the sensor, looks fine)



Car misfires on idle, will stall on idle, and will not go 1 block without jerking horribly or dying! There is also a gasoline smell!

Any suggestions help! Thank you



Parts replaced/ modifications:

Ipd intake

Ipd tcv

Snabb intake pipe

New maf sensor

New acceleration sensor

New spark plugs (gapped .28)

Ipd wires

New cap and rotor

Msd ingnition coil

Air pump delete (No cel)

New pcv system with new lines and sensor cleaned at intake pipe

New gas cap

Cleaned IAC valve

New vaccum lines for TCV

New purge valve

New evap valve

New intake manifold gasket

Timing belt done

New fuel pump

New fuel filter

New O2 sensors

New fuel pump relay

Muffler delete

 

Well, according to my code reader manual. P0300 is a multiple cylinder misfire, P0301 is cylinder 1 misfire, P0302 is cylinder 2 misfire, P0303 is cylinder 3 misfire, and P0304 is cylinder 4 misfire. So the only cylinder not misfiring is cylinder 5. With so many cylinders misfiring, it is doubtful that the spark plugs are bad, but if they are not NGK, or Volvo OEM, I have found that our cars did not like them and we had problems. That said, I am leaning toward a common item causing the problem. Check for a vacuum leak, a loose/split turbo to throttle body hose, loose connector to IAC, or other sensor. If it is a bad part my guess is a bad/weak coil, bad distributor cap or rotor, or bad plug wires.

 

if you smell fuel, then check fuel pressure, look for leaks. Did you check the fuel pressure regulator? could have a torn diaphram sucking extra fuel into the intake. Are the plugs a normal tan color or black/wet looking?

 

yes the plugs have this pitch black soot on them but it is dry not wet looking. And i will check the fuel regulator