98 Gs300 Cylinder Misfire/exhaust Backfire

[98gs3]

Hey guys, I have a 98 GS300 with over 100K, I got a check engine light, Random cylinder misfire and cylinder 5 misfire. The car runs rough, shakes when accelerating, sometimes with a bit more acceleration it will backfire, real loud noise. 3 years ago Lexus replaced a bad fuel injector. Any suggestions what could be wrong now?

[dcfish]

Hey guys, I have a 98 GS300 with over 100K, I got a check engine light, Random cylinder misfire and cylinder 5 misfire. The car runs rough, shakes when accelerating, sometimes with a bit more acceleration it will backfire, real loud noise. 3 years ago Lexus replaced a bad fuel injector. Any suggestions what could be wrong now?

Injector again :cries:

[98gs3]

Is it an injector for sure, should I order one? The codes were: random cyl misfire, cyl 5 misfire, and random cyl misfire again.

[dcfish]

Is it an injector for sure, should I order one? The codes were: random cyl misfire, cyl 5 misfire, and random cyl misfire again.

Maybe a cracked plug and/or wire is shot.

[98gs3]

I nevery replaced the plugs/wires, is it hard (specifically for cylinder 5)? AutoZone told me the wire set comes with only 3 wires, is that normal? What about the coils? Is that something I can check myself?

[99blkgs]

you need to replace your plugs all you have to do is remove the throttle body and u can get to all of the spark plugs easily. if you have never done them its about that time

[98gs3]

I can't tell you guys the exact mileage on my car, 1.5 years ago my odometer just stoped and showing 79,xxx mileage for the past 1.5 years. So I am sure I am pretty close to 100K. Is doing spark plugs sufficient, or is there wires/coils involved as well? Any recommendation where to get a cheap fuel injector just in case?

[dcfish]

I can't tell you guys the exact mileage on my car, 1.5 years ago my odometer just stoped and showing 79,xxx mileage for the past 1.5 years. So I am sure I am pretty close to 100K. Is doing spark plugs sufficient, or is there wires/coils involved as well? Any recommendation where to get a cheap fuel injector just in case?

OEM injector only.................Cheap = Failure :cries:

[98gs3]

anyone knows a part number on the fuel injector?

[99blkgs]

anyone knows a part number on the fuel injector?

u only need 3 wires because the rest are coils and yea u definitely need a tuneup at 100k miles, get some ngk plugs and ull be good.

[JDMSedan]

I can't tell you guys the exact mileage on my car, 1.5 years ago my odometer just stoped and showing 79,xxx mileage for the past 1.5 years. So I am sure I am pretty close to 100K. Is doing spark plugs sufficient, or is there wires/coils involved as well? Any recommendation where to get a cheap fuel injector just in case?

OEM injector only.................Cheap = Failure :cries:

I can tell you right now that you are waisting your time and money just "throwing parts" at your car. How do you know there IS actually a problem with the injector? OBDII codes will only give you a direction to look in, it's not a magic road map to every problem that may go wrong with your car. There are a few simple tests you can do if your interested.

[98gs3]

I am interested, what do you have in mind? I don't think it's an injector myself.

[mehullica]

If you don't have access to a datalist scantool, or don't want to pay for a diagnosis. Take the plug, and coil for another cylinder and swap them with #5. Check the resistance of the #5 wire. See if your misfire moves another cylinder. I have seen many porous heads leaking coolant around the plug #5 shorting it to ground. I have seen some bad coils also, they fire 2 cylinders each and one side fires but the other doesn't. Hopefully you don't have a porous head, since you'll have to replace it to fix the problem.