New to site, got a problem

[Rschmitt]

It started with a slight shake at idle. Then when im at any speed and the rpms go to about 12k it shakes the whole vehicle. When i give it more gas, the problem goes away. i am running the codes saying cylinder 4 misfire and misfire detected at startup. also some 02 sensor codes which i feel arnt related. I went to have it looked at and was told the coil pack needed replaced along with plugs and wires. he wanted $500. i did it myself except for the coil pack. he put an old coil pack that was rusty on and i didnt notice at first. but its new now. Anyhow, i still have the issue. i ran the 3m fuel system cleaner, changed plugs, wires, coil pack, and i cant think of anything it could be. Ive searched the forums, not finding anything, maybe i didnt search long enough. 2002 explorer xlt 4.0 4wd. im desperate to fix this, its cost me wayy to much. and i need to be able to drive 600 miles down to nc without an issue. im scared to even leave my town. the last time i drove down to nc my wheel bearing exploded.

 

[BobWiersema]

I think you should do a compression test.
I dont know that much about the 02's, is that a SOHC engine? The O2 sensor codes are just because of the misfire, the sensors are soaked. Sounds like you have done everything you should so far. My next step would be compression test. I wouldn't drive it like that, sorry about bad news but, you just shouldn't drive it with a misfire, you will create so much more damage.

Bob

 

[Rschmitt]

i mean, i have to drive it to work. which is only 2 miles or so away. whats the compression test going to tell me? ive heard that somtimes coolant leaks in through a bad manifold gasket. i just had my oil changed at valvoline, im pretty sure they fill the coolant and my resivoir is half empty.

Edit: im pretty sure its the sohc engine

 

[BobWiersema]

i mean, i have to drive it to work. which is only 2 miles or so away. whats the compression test going to tell me? ive heard that somtimes coolant leaks in through a bad manifold gasket. i just had my oil changed at valvoline, im pretty sure they fill the coolant and my resivoir is half empty.

Edit: im pretty sure its the sohc engine

Compression test on a engine is like blood pressure on us humans. So much can be learned. So far you have done everything you should. Coil pack, wires and plugs. If that doesnt fix a misfire we need to know why its not firing. It could just be a bad injector but a compression test is so much easier then pulling out injectors so start there. If you can change a spark plug you can do a compression test. If you dont have a gauge try Advanced Auto for free tool use (if you have AA out in Ohio). BTW if thats a SOHC engine its marked on the intake manifold cover, ie 4.0L SOHC. It is also on the white tag left hand side of the radiator bracket, you cant miss it.

If you only need to drive 2 mile, you should be ok but take it easy. And the antifreeze bottle should only be about 1/3 when cold, so that sounds fine.


Bob