Cylinder 4 misfire 1999 3.4

[martyj96]

I have a 1999 4 runner 3.4. I have a cylinder 4 misfire, I changed out the coilpack, sparkplugs, wires, did a compression check. It runs great at start up, but once it warms up it starts to misfire... I'm thinking maybe the fuel injector. I wanted to see if anyone has had the same problem before I tear into to replace an injector. Thanks

 

[greasmonkey]

ive got a 2 and 5 misfire right now. fuel injectors were the next thing i checked. its not too hard of a job to change them. just dont pinch the o-rings.

here is my current status:
98 3.4L

well. Ive got 300,302,305

started as only flashing at highway speeds while decelerating or coasting with throttle depressed slightly. would quit flashing when i gave a little more throttle. is now coming on more frequently
i feel no distinct miss, ever. just a noticeable lack of full power, pulsating engine while driving
New plugs, wires, fuel injectors (6), fuel filter, air filter, air sensor at the intake
swapped coils, codes stay the same
Declining power, fuel economy, and Moral

 

[martyj96]

I replaced the injector and so far so good. It is running smooth.

 

[BrianSD_42]

ive got a 2 and 5 misfire right now. fuel injectors were the next thing i checked. its not too hard of a job to change them. just dont pinch the o-rings.

here is my current status:
98 3.4L

well. Ive got 300,302,305

started as only flashing at highway speeds while decelerating or coasting with throttle depressed slightly. would quit flashing when i gave a little more throttle. is now coming on more frequently
i feel no distinct miss, ever. just a noticeable lack of full power, pulsating engine while driving
New plugs, wires, fuel injectors (6), fuel filter, air filter, air sensor at the intake
swapped coils, codes stay the same
Declining power, fuel economy, and Moral

[MENTION=112176]greasmonkey[/MENTION]

Did you do a proper compression test?

Is it blowing smoke or burning coolant. That sounds like a legitimate miss and its happening in multiple CYL. I wouldn't throw any more parts at it until you get the compression checked out.


As for OP ... well yours doesn't sound quite as serious if it isn't showing a loss of power or continuous miss.

 

[drallan]

I had the same thing. Forget what code it was. Was intermittent at first, would run rough for first 5 min or so, then smooth out. Until eventually it stopped smoothing out. Was worse when the car was off for only a few min, like running into the store for 10 min. I Replaced the 3 injectors on the drivers side and fixed her right up. Been solid for 6 months now. Plan to do the passenger side this spring when I can save up the $$ for 3 more injectors.

Just be very careful popping the old injectors out. Had the plastic tip on one of them break off and stay in the block. Had to use a pair of tweezers and a shop vac to pull the pieces out. Shop vac was to prevent any little chunks of plastic from falling into port. Had wife hold the vac nozzle as close as possible to injector hole while I pryed out with tweezers and a small blade screwdriver, the kind you use on glasses.