RTorrez1

Like I said before, Take it in and have the codes read. This will give you a place to start so you don't have to keep throwing parts at it. When the CEL keeps coming on it is telling you where to start!

Mikeythrash

I know the codes it doesn't tell me anything but multiple misfires I have got all 6 misfiring then it changes and just 2 and 4 misfires and got the famous P0300 code random misfire.doesnt tell me where or how it is misfiring.So that why I did not take it in cause there just gonna try and replace stuff that i can replace myself.now after I do this stuff and it continues then I'll think about taking it in.I don't know any mechanics that know jeeps other then the dealership.not trying to spend 200$ for someone to tell me what I can do at home.

Mikeythrash

Also this has been happening for A year now had a blown head gasket got the head machined cut and whole new kit.has all new hoses and everything else.only thing I can think of is fuel injectors and IAC sensor. That has not been replaced.it does have cylinder 2 and 4 new injectors cause they were the ones missing. But still continued to miss after that also

JuanSchwartz

If you had head work done +- a year ago, a new manifold gasket would most likely have been used, so not sure how that would already be dry rotted. If for some reason someone reused the gasket, I would imagine there is a substantial vacuum leak somewhere around there. A vacuum leak can definitely cause erratic idle. Can also play hell with the a/f ratio, since the ECU freaks out about the extra air. That could indirectly cause misfire codes based on plugs fouling out.

As for potential vacuum leaks, there are a couple of ways to check for leaks, and i would probably start looking for one or more of those as well before i started replacing sensors. Likewise I would expect that any new plugs, regardless of manufacturer, will foul out in short order if you don't find/repair the root cause first.

Mikeythrash

Hey the head was done around jan/feb. And no he did not replace the manifold gasket here is a pic of the manifold gasket



Looks pretty dry rotted to me

CCKen

If you're planning on replacing the intake/exhaust gasket, I highly recommend an OEM gasket from the dealer. They're not that expensive. OEM gaskets are impregnated and the intake and exhaust ports are on register, unlike some aftermarket gaskets, like Felpro.

Firestorm500

I've never heard of anyone reusing intake or exhaust manifold gaskets.

The aggravation of having to go back in there to fix a leak is just. not. worth. it.

BlueRidgeMark

I don't know what you mean by "dry rotted". From that picture, it's hard to say whether that gasket was replaced or not. It would have to be a pretty stupid shop to re-use a manifold gasket. Most of the time, it would be more trouble than it's worth because the gasket is usually at least partly stuck and has to be scraped off.

You could have vacuum leaks in a lot of other places, too. Do a search on Youtube and you'll find videos showing how to find vacuum leaks. I wouldn't be buying parts and turning wrenches until you've done some more homework.

JuanSchwartz

x2 on what BlueRidgeMark said. don't buy anything till you know exactly what the problem is.

Mikeythrash

Shop didn't do the work a guy I know in his garage did at his home. And also I checked the light today and I for codes for 304 and 306 so cylinder 4 and 6 are missing and got a code for random misfire which was 300

Firestorm500

I've seen bad head gaskets cause that.

BlueRidgeMark

Can you ask him if he re-used the gasket?


There are a lot of things that can cause those codes.

Mikeythrash

Yeah I know the head gasket is good so that's not the problem.The intake manifold gasket that is old and I think there is a vacuum leak there I also think my IAC sensor is bad.I cleaned it also and didn't really do anything and it usually misses at around 40-55 mph

Mikeythrash

It also sounds like it's all cammed out. Like I have a 350 small block in it haha

Firestorm500

Do you have any unexplained coolant loss?