Cylinder 4 misfire

Have a 97 tj with just over 23700 miles the other day my computer threw a 304 code for the cylinder 4 misfire the plugs wires cap and rotor plus the coil are all new what could be my problem or problems atvthis point thank u

Maybe one of the new parts that you put on is defective. It happens. Once i had a plug that would misfire under preasure but would look good in the testing machine. I would start by checking to see if you are getting power to the plug.
On my 99 I had a misfire code when the intake air temp sensor was dirty (on the intake near the throttle body) I sprayed it with some mass air flow sensor cleaner...

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I checked the spark gettin good spark and to that plug and u can smell the unburt fuel in the exhast i havent chevked that sensor yet but ill give it a shot i was gonna look over my wires to it was doing a random fit wear it would spit and sputter threw driveing rang for like a month and now its throwing a code for just cylinder 4 i was gonna check over my wires on my injectors and my crank sensor does anyone think that that would cause just one cylinder to missfire and is threw its fit with the spit snd spudder threw driveing rang befor i changed my coil and ext its my dailey driver and my weekend worrier but ive been driveing it the way it is kills my fuel milsge and im sure is not healthy but i need to get to work thanks for ur idea ill check them out if anyone has any other suggestions please let me kno thanks craig

You said that it throw a code for the 02sensor also, have you replaced that?? the 02 sensor tells the computer what air and fuel ratio to use, if it is bad it will misfire.
So i went to auto zobe to scan my codes again to see if snything chsnged now i have a cam position sensor but i dont have that on my engine and still throwin the code for it running to lean in bank one??

I pulled my intake air sensor to try and clean it and it was covered in a layer of black goo but i still dont understand y its throwing a cam sensor code when i dont have a came sensor
See thats what threw me for a loup its not actually called a cam sensor thank u i guess for 25 bucks ill just change that first and see what it does
I was getting a 302 error code and made the mistake of resetting the error codes. My mechanic told me 1) not to reset the codes as it takes three consecutive errors to trigger the Check Engine light and a 302 code (or any specific cylinder misfire code) is too general to track down the problem. He spent over an hour checking everything that we did to my '97 Grand Cherokee 4.0L 6-Cyl 4x4 that included a head gasket repair ( heads were warped and not cracked and I invested in the repairs), replaced the fuel pump (hard starting and only on second attempt), changed pulleys and A/C Compressor, serpentine belt, bad sensors etc - over $4k in work but I've owned it since it was new almost 18 years with 153,000 original miles and in excellent condition (all service records kept and garage kept in Southern California Desert area). Hardly a scratch, no rust - I'm just in love with this model because of the beautiful Red finish and the plastic side panels that kept it from being Dinged.

Back to the the problem, it's been occasionally stalling and misfire ingredients, but I can't find the problem and neither can my mechanic. I started keeping it more than half full, changed hoses that were wearing out and put on a new gas cap.

Mechanic told me to stop using the fuel injector cleaner as that engine uses the engine heat to remove carbon buildup. He also said that the engine computer board requires three errors before it throws a code and since he couldn't find anything wrong he told me to run it until it those another 302 code but not to reset the error code. If I continue to run it it may throw another code to help narrow down the problem. So far it's been 3 months and it hasn't town another 302 code. I haven't been driving much as the temp in the desert here is around 115 degrees in the summer so it might start acting up again in winter when the temp drops to the 70's in the daytime.
One thing I did notice is while keeping the tank close to full I'm not having as much trouble but when I was misfire get I was typically below half a tank. I'm also retired and my mechanic knows that Zi can't keep trying to change out plus, wire or injectors while my wide and I have disabilities so he is doing the diagnostics step by step until we find out just what it is. Almost everything under the hood is new or grinder and flattened so there are no leaks. It turns over first time since replacing the fuel pump but it is only the second fuel pump I've had in 153,000 miles. That and hose replacements after getting emission error leaks and I couldn't find another 97 in as good a shape. I love the early Wisconsin built in-line six engines. Mostly mechanics and very little computer technology to deal with.
I'm sure you know the attachment you get after owning a new car for almost 20 years.

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