Mudgoose1969

i have a 99 Grand Cherokee Laredo 4x4 with 4.0 in it. No codes now but did have a P0141 code before found bad fuse for 02 sensor problem is when first start it runs fine in park or neutral but when go to drive it sounds like its missing and burping unless i floor it then its fine but not a low rpms if i shut it off and start again it usually comes out of it. After driving for a little bit it runs just fine. It has the California emissions system with the 4 O2 sensors on it. i have put in all new plugs and everything else is running great. Any ideas and i also have a brake light and airbag light on all the time. Put all new brakes and e brake works fine any info would be great need to fix to get inspected and tagged.

Creature85

Check for codes again. It sounds like vaccum line issue or an O2 issue. I'm thinking the latter.

dave1123

California emmisions or not, I can't figure out where they'd put 4 02 sensors on the 4.0. I've never seen more than 2, one in the exhaust manifold and one after the convertor.

My 97 ZJ had this exact same problem. I cleaned the throttle body and replaced the TPS and 02 sensor (upstream one), and it got better, but it didn't go away. After the fix, it only did it on cold wet mornings and only for about 3 seconds. I just waited it out and never pulled out of my driveway in front of anybody. Worked for me.

One of my mechanic friends suggested it was a carbon canister purge solenoid malfunction. IDK because I never bothered to do more about it. I did occasionaly get a CEL saying "small evaporative leak."

Is your brake light an ABS light? If it's ABS, check all 4 wheels for a damaged or mismounted sensor. The airbag light is something I'll not deal with. My brother had one go off in his face for no reason.

Mudgoose1969

yes its an abs light i guess and will check the sensors as for the 4 O2 sensors there are two pipes coming out of the manifold with two mini cats one sensor before both mini cats and one after on both pipes i thought the same thing till crawled under it here is a picture

Bustedback

Put a fuel pressure gauge on the test port on the fuel rail, start it up and watch the gauge, it should go up around 45psi. Now shut the engine off and watch the gauge again, there should not be a huge drop in pressure once the engine is off. Leave the gauge on over night and see if there is any pressure showing on the gauge. If you nothing, you have a failing pump. Cycle the key a few times before starting the engine to prime the pump and see if that helps.

dave1123

WOW! California really does things in a big way, but not always the best way. That system just seems TOO much! I'm sorry to question you.