well i havent been active at all for some time now and im having some some problems out of my 4.0 ohv so i thought i would get some help here. well i bought and upper gasket kit and had a buddys dad put them on, well i drove the truck for about a week after he does it and all the sudden my motor RUNS LIKE CRAP. miss firing like freaking crazy. well some guy checked it over with a snap on scanner and he found i that there was a cylinder 4 misfire. well we narrowed it down to it being the injector so he replaced that today. it just so happens it runs better but still horible. i unpluged the egr valve and i thought it was running better but still bad. im lost on this on. its driving me crazy. i just dont know what to do with out possibly wasting money. any ideas?

have lean codes for banks 1 and 2 btw.

help and info is greatly appriciated

 

Maybe the person who installed the gaskets screwed it up. Maybe something was over/under torqued, not properly cleaned off, etc. There is really only one way to make sure something is done right, do it yourself.
There is also a very good possibility that the lower intake manifold gasket is bad. By replacing the upper gaskets only you are gambling. Sometimes it works, sometimes it doesn't.

 

always god damn cyl number 4 on these trucks. LOL head is cracked most likely add a little Bars leak to the coolant and see if it fixes it same problem my truck has.

also FYI, I am on coil pack #2 due to failure random misfire. as for the lean codes replace your o2 sensors if your heads were cracked if coolant got on them it will wipe the out. I do a driver side o2 ever time i get the miss fire back, seems to always go.

 

o2 sensors were checked with the scanner and they are fine. #4 is no longer misfiring due to replacing the injector. the lower intake gasket was also replaced. btw the guy who replaced everything cleaned absolutely everything so i know its all clean. i watched him do most of it.

im thinking its EGR related since ran better with the egr unpluged.

and thanks for some info stone, its good to hear info from someone that has experience with the same engine.

 

me and stone have had em same problems lol always that durn number 4 cyr. it may be egr i dont know that one sense my truck never had one to start with

 

Intake gaskets prob wont solve the problem, all OHV heads like to crack at the HEAD at the head gasket level not intake . causing coolant to enter the chamber and cause a misfire its very common on the #4 cyl.



Same here no EGR thank god

 

Are trucks don't come with a EGR? I'm not sure what your problem could be. I would check the EGR to since it seemed to run better with it out. Dang I hope my OHV does not incur that head problem. That does not sound like fun.

 

yes there is trucks with out EGR most 2000 dont have them.

and its not a matter of IF it will have a cracked head its WHEN.. all OHV have it happen its very very common. SOHC have cam chains we have head problems

 

Geez, then I'm really surprised mine hasn't cracked yet. I don't drive it with ease at all really. How much does it cost to get that fixed?

 

when you buy yours with what miles it might already be done they like to do it around 100ish.


depends just cost of parts or if you need to take it somewhere. there is supposedly better heads out there that dont crack idk all the one's i have seen have had it happen at some point in time.

 

well i got frustrated with it and a friend of mine took it to someone he knows who is great a diagnostics. took him five hours but he found 1 the #4 injector WAS bad like we had thought, the egr soleniod IS bad. (its all unpluged now) and the thing causeing the most problem was a spark plug the looked to be fine and fired about half the time. but hey its running great now! got all my power back!

 

i had the exact same problem, ended up being both heads were cracked. It was NASTY when i took the heads off.. Green **** EVERYWHERE.. i ended up replacing ALL The gaskets, heads(complete heads with new valves and springs) and pushrods. truck ran like a top afterwords! if it is the heads, plan on spending around 1100 to fix it, thats just for parts