1993 Other Volvo Models Volvo 440 turbo missfires at low RPM

FOTOVORTEX

MEMBER
1993 VOLVO
4 CYL
2WD
MANUAL
50,000 MILES

I have a 440 turbo, it hard starts and missfires a lot in low rpms. When I run it on over 3000 rpm the car runs fine. I tried to replace sparks, spark plugs, air mass sensor, lambda oxygen sensor, hot water sensor, but the problem is still here.
If I disconnect the air mass sensor, the car is running at 3400-3600 rpm, and without missfires.

1 Reply

DOCHAGERTY

MECHANIC
9,601 POSTS

There might be several issues at play with your Volvo. Fuel pressure and delivery, proper ignition timing and quality, adequate power and grounds that are free from issues (corrosion or loose connections) maintenance items up to date. I know this sounds generic in nature, but oftentimes it can be very difficult to deal with problems from cyberspace and can often start with checking and eliminating the basics and then moving towards the more esoteric. It may also require seeking out a local expert that has access to sophisticated diagnostic equipment that most folks cannot afford.