CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Misfiring badly on three cylinders

I have a 2003 Jeep liberty with about 195,000 miles on it.

All of a sudden it’s misfiring pretty badly. I was able to park it for a few minutes the other day and drive home 40 miles normally, but the next day it didn’t seem driveable at all.

There’s a small evap leak code and a random misfire code. Also, misfire codes for cylinders 4 5 and 6, which would be different sides of the engine.

I’m not sure of the evap code could be related or not. I’m thinking that faulty fuel injectors / plugs / ignition coils sound unlikely because it’s multiple cylinders all of a sudden? Compression-related problems sounds more unlikely to me because it’s multiple cylinders on multiple banks.

My best idea is a failing fuel pump, although I don’t presently have a pressure gauge.

Any ideas?

If a SWAG will get you started look for a leaking upper intake.

I believe the Jeep Liberty was well known for having top end . . . as in cylinder head . . . problems

V6 I assume? Intake manifold could be issue. Is it plastic intake or cast alum? Does it have a single coil pack? Or is it COP?