95 explorer 4.0 running like crap HELP

[louisianaqueen]

My husband has a 95 explorer 4.0 that we just can not get to run right. It is idling rough. It is hesitating to accelerate. The rpm's when coasting will drop almost to the point of the engine dying but just before it dies the rpm's will pick back up.

Everything we have done so far.

Had the cylinder heads checked for cracks and to see if they were warped. (they were warped so they were machined down the guy that did it didnt tell us how much he took off)

Replaced all the gaskets from the heads up.

Brand new injectors

brand new fuel rail

brand new fuel pressure regulator

new plugs

new plug wires

new ignition coil

new mas air flow sensor

new throttle position sensor

new fuel relays

new EGR valve

new EGR valve pressure sensor

new pcv valve

replaced all the vacuum lines

new air filter

cleaned the throttle body

new egr valve tube

new idle sensor

new fuel filter

did a oil change

new oil filter

new fuel pump

We are at a stand still and do not know what else could be the problem with this truck. Any help is greatly appreciated.

Thank you in advance

 

[J_C]

Pull the OBDII trouble codes. Now that you've replaced so much (wow!) it may be time to do some measurements, like fuel rail pressure and cylinder compression, and if you replaced multiple things at once, to double check the work to make sure no vac lines or electrical connectors were overlooked.

edit: I assume you got the spark plug wires back onto the right cylinders. Did any of the old plugs look different than the rest?

edit2: I suppose they probably did if you had a warped-head, leak, but was the machined head repair verified as fixed, no leaks now, good/near-equal compression on all cylinders?

 

[Fordman999]

Pull the OBDII trouble codes. Now that you've replaced so much (wow!) it may be time to do some measurements, like fuel rail pressure and cylinder compression, and if you replaced multiple things at once, to double check the work to make sure no vac lines or electrical connectors were overlooked.

Yep I agree could be a vacuum line leaking causing rpm fluctuation. You should have gotten some sort of check engine code. If not it more than likely is a hose in the engine that is "shafed" or just broken. They're hard to notice use a good strong flashlight.

 

[Big Z]

My first test would be the ol brake cleaner/fuel trim check. See if they drop into the negatives with brake cleaner sprayed around the intake manifold/plenum/vac lines.

 

[J_C]

I'd also take the belt(s) off and run it for a BRIEF period to see if that makes the engine run smooth... thinking it's possible the bearing on something belt driven is shot and loading down the engine, though I'd expect it to wobble or make a racket but they don't always.

Additionally, check the battery voltage, both with engine off and running. A parasitic current leak or shot alternator could be causing misfires due to low voltage. We may be telling you things that you've already done. :scratch:

Did the head warpage cause coolant in the oil and if so, is it possible it ran with bad oil for long enough to cause internal damage? Was it running good after the head work, or never ran right since then?

 

[alohamonte]

can you rule out a vac leak or misfire? Possible bad/cracked plug?

 

[boominXplorer]

What plugs are you using?

 

[96eb96]

That really sounds extreme, Sounds like you are throwing parts to solve a problem. Without a scan tool though it may make sense, because lots of things are just a guess. I would start checking for Clogged cats or exhaust obstruction.

For 95 you should buy a cheap snapon MT-2500 red brick scanner, which can read data. They are under $200 on ebay, you don't need the more expensive ones with newer years. 95 isn't OBD2, so you can't really use the mainstream scan tools. You could flash codes but if the CEL isn't on you won't see much. With a scan tool you can see certain parameters that will lead you to a diagnosis.

 

[Nolastcallss]

following. i am having the same issue with my 95 explorer i haven't replaced everything on your list but pretty close. have you found a solution to your problems yet?

 

[koda2000]

I assume with all you've done you did a compression test? That's the cheapest and easiest way to check an engine's internal health (valves/rings/compression).

I once had a pre-ODB Chrysler V6 and it started running really badly, especially once warmed up (no power, near stalling in take-off) I don't recall if the idle was effected. I flashed the codes and it said it had a bad O2 sensor (I think it only had one). Sure enough, replaced the O2 sensor and it was running normally again. I don't see that you've replaced the O2 sensor(s) in your long list of parts.

 

[happydave12]

I have the same issue although the only code I get say EGR. HOWEVER passenger side front cylinder was dead.I replaced plug wires and put platinum plugs which got cylinder firing again but at low rpm/idle I have a terrible miss. Compression is good in all 6 cylinders, wondering if maybe the fuel injector for that cylinder might be the issue. Any feedback would be greatly appreciated.I've been dealing with this for months. I'm on permanent disability and can't afford to take it in for repairs, kind of stuck at this point. Is it possible that the EGR is also an issue besides the wires & plug. Thank you

 

[J_C]

Dave, I'd clean the whole EGR tract, make sure there's no leak, and if that doesn't fix it, try putting Techron fuel injector cleaner in a half a tank, and after a while if it's still happening I'd get a set of injector o-rings, pull the fuel rail and swap the position of the injector on the cylinder that's not firing with another cylinder to see if the problem moves with the injector, but while the fuel rail was out, I'd turn the key to see if the suspect injector is spraying fuel out.

The replacement O-rings are just to make sure they seal good when you put it back together. You could also check with a multimeter to see if power is getting to the injector and there's a pulse reading running, similar to the others before taking them out, in case it's electrical.

 

[happydave12]

Dave, I'd clean the whole EGR tract, make sure there's no leak, and if that doesn't fix it, try putting Techron fuel injector cleaner in a half a tank, and after a while if it's still happening I'd get a set of injector o-rings, pull the fuel rail and swap the position of the injector on the cylinder that's not firing with another cylinder to see if the problem moves with the injector, but while the fuel rail was out, I'd turn the key to see if the suspect injector is spraying fuel out.

The replacement O-rings are just to make sure they seal good when you put it back together. You could also check with a multimeter to see if power is getting to the injector and there's a pulse reading running, similar to the others before taking them out, in case it's electrical.

Thank you, I'm on it. I'll post my results shortly

 

[jmvb]

Double check if the vacuum line connected to the EGR is the right one...
Once, by mistake, I swap that for the one which go to the evaporation charcoal canister, and the engine ran dreadful