So for the past few days the truck has not been running good at all. It misses and sputters. It does it the worst at 3000rpm and above but i idles rough also. I was on ice one day and i hammered on the truck and it rit the rev limiter a pretty good amount and it seamed like it started doing it then but im not sure. The oil is clean and full the coolant is full and also clean but on the filler neck for the oil there is foam built up which i always assumed was coolant in the oil but since both the oil and coolant are clean i dont think thats the problem.
The truck has all new Plugs wires and coil packs coil packs. Could this be a fuel problem perhaps?
Thanks for any help.

 

the 5.0 isnt a very high RPM motor. last time i revved a low rpm motor high for a long period of time i spun a bearing. (my old grand prix)

but maybe fuel, sounds like what my friends honda started doing. it ran really sh!tty for a day or two then just wouldnt start. fuel pump went just like that.

 

Sounds like a timing issue or a fuel issue like you said. Try changing the fuel filter and see if that fixes it... Probably your cheapest option atm.

I would also look at head gasket, intake gasket.... That could cause it to run sh!ty too.

 

Check your fuel pressure. Make sure your getting enough, that should tame any of your fuel worries. You could have also damaged a valve with the higher RPM's if you think that has something to do with it. The stock valve springs aren't the best and tend to float by 5400 RPMs.

 

sounds like a fuel pump taking a poo or a filter got clogged. Fortunately they are both pretty cheap to replace.

 

Well im going to check fuel pressure tomorrow and see if that checks out okay or not. Im hoping its just fuel pump/filter they do have 180,000 miles on them.
I wouldnt think i damaged anything internally i only hit the rev limiter for maybe like 5-6 seconds but who knows.
All the intake gaskets are new so they should still be okay only other thing might be a head gasket which isnt that big of a deal just a PITA.
Thanks

 

My junk hits the limiter quite often and I have never had any problems. Has the problem gotten progressively worse? If you did any internal damage you would know it, so dont get too worried about that.

 

My recommendations:

Change the fuel filter first. If no change, check fuel pressure as previously suggested. If fuel pressure meets proper specs (and all components of ignition system are OK) then remove all spark plugs while carefully inspecting each plug for irregularities (or inconsistancies between other plugs) and take a compression test.

If your compression results are good & consistant and all the plugs look the same (and since you already mentioned that the oil looks good) . . . then it's NOT likely a head gasket or valve problem. No need to tear the engine down looking for ghosts that are not there.

If still problems (and no diagnostic codes . . . assuming you're using OEM EFI) you might check the timing and watch for "jumping around" of the timing while at idle which would indicate timing chain problems.

Those are the steps I'd take if it was my own engine. Hope that helps and good luck !

 

Well i didnt have time to do anything today in school but tomorrow first thing im gonna check fuel pressure and hook the scan tool up to it. Then go from there

 

So the fuel pressure is 40PSI. All the plugs were good all pretty clean and all look the same but i regapped a few and put them back in also put in a new fuel filter which didnt help either. So then i put the scan tool on it and got 3 codes i didnt have before the one said that bank 1 was running rich the second said that bank 2 was running rich and the third had something to do with the cam positioning sensor so we are going to test the sensor tomorrow and see what else we can find out.

 

Is that at idle? With or without the vac line connected to the regulator?

 

That was just turning the key over without the engine running i was told to do it like that. What should it be Bob?

 

There are a couple of different ways to check it properly. Check it while idling, idling with the fuel pressure regulator unhooked, and usually on throttle to see if it drops off hard. I can't remember all the exact pressure for an explorer but its something lie 32-35 on idle, about 40 to 42 with the regulator unhooked, and somewhere between 30 and 40 under throttle. If it ever starts dippin into the 20's you have issues.

 

About 40 PSI is correct because there is no vacuum to the regulator with the engine off. When the engine is idling in neutral, the regulator should have about 20" of vacuum applied and you should see a fuel pressure of roughly 30 PSI.

 

Okay so the cam sensor was bad and the housing for it was also. I replaced both those and i am still having the same problem. I am begining to think it may be the valves collapsing cuz it only does it at high rpm and under a load when the motor is working its hardest. I dont have any other codes that are comming up and i really dont know of anything else that would cause it to do that. What do you guys think?

 

I had a problem with a timing issue with my 5.0 in my 89 GT . Not sure how you have yours set up but I replaced that little plastic module in the wire loom that splits off from the distributor cap. It about the size of a Lego, I forget what its called but when I looked in at the tabs they were both slightly corroded. I cleaned them up and it ran better. The name of it has nothing to do with "timing" probably why I can't remember it.
Good Luck...

 

^--- I think your talking about the Spout connector, but I believe he doesn't have a distrubuter since its an explorer motor.

 

Yeah, like I said...not having anything in common with timing, sounds like a lawn tool to me.
thanks,

 

So no codes, but still runs bad?

 

SPOUT = SPark OUT

 

No new codes and still runs bad. And yes i do have that litle spout connector i pulled it out and it looked fine no corrosion at least.

 

Have you done a compression and cylinder leakdown check on it? Those should tell you if you have a valve problem.

 

Yes all cylinders are about 110-115 psi compression. and leak down was about 45%. So i would say it needs a valve job.

 

Okay so the cam sensor and housing were both smoked. I replaced both of those still no differance really. Um i did fuel injection cleaning/blocked off egr/fixed some vacume lines that werent hooked up right/o2 sensors are fine/new fuel filter/regapped plugs(they looked great so i didnt replace em)/fuel pressure test with KOEO gonna do a WOT test tomorrow or monday/getting new plug wires monday there motorcrafts bran new for $50/then gonna gap the plugs again just to be sure there good.
What else can you guys suggest before i pull the heads?

 

lol, you might have bent some valves if you floated them at high rpm.

usually good compression on a 5.0 is around 150-165psi per cylinder...