Help with misfire

I have a 1996 4Runner 3.4 ltr.

I have a bad sputter especially when getting into the gas - starting off or going up-hill. I could not get a code for almost a full year. The I finally got a p0302 code. So I started throwing parts at it.

I replaced:
- all 3 Coil Packs
- all spark plug wires
- all spark plugs
- all 6 fuel injectors
- both O2 sensors
- crankshaft sensor
- ran 2 cans of 44K

Each time I replaced one of these parts, I tested and the problem still persisted. The problem still persists. I have spoken to numerous mechanics as well as auto parts stores. No one can pinpoint the problem.

Does anyone have any suggestions?

 

Well for one thing you're in the wrong section for a 96, which is probably why no one has offered any help. @Bob any chance of moving this to the third gen section?

As far as your issue, has this problem been there since you got the 4runner or is it a newer issue? To me, it kind of sounds like its a timing issue. When I replaced the water pump on my camry it did the same thing, so I pulled the timing belt back a tooth or two and it went back to normal.

 

As soon as I clicked Post I realized I was in the wrong forum, sry about that.

I had the truck for about 6 months before I started having the problem. I've been working on it for a little over a year trying to solve the hesitation problem.

Would the diagnostics pick up a timing issue? I am using an old CarMD.

 

Lol its all good. Just figured I'd say something since we're not as accustomed the the 3.4 here.

To be honest I'm not sure if diagnostics would pick up a timing issue. Most of the cars I work on are pre OBD II. Tell me if this sounds familiar, it idles fine but then starts to sputter around 2-3000 rpms?

 

Thanks again for the reply.

It sputters when taking off or going up hill...any time I have to get into the pedal. However It seems to idle perfect. I put a new Fuel Filter on this afternoon but of course that didn't make a difference.

 

Hmm my money is still on the timing but I could easily be wrong, the 3rd gen guys would be the ones to ask

 

Hi! What did it end up being? I have a 1999 with only 104K miles and i've got that error p0302 misfire cylinder 2. Replaced plugs and wires and as soon as it gets hot.. rough idle

 

You need to do a fuel pressure test. Sounds like a weak fuel pump or bad fuel regulator.

-Mike

 

Pull the plug on that cylinder after it's been running bad for a bit, see if the plug tells you a tale.

I'd do a coolant test for exhaust gases. It's typical that when a head gasket starts going bad, it's worse when hot.

Also, swap the coil packs around. If the misfire moves you know it's a coil pack.

Also, you can swap injectors around. Again, if the issue moves, it's a bad injector.