I just recently bought it in January, and i've pretty well grown up around mechanics my entire life, so I do know a few things, but not so familiar with the computerized engines. I recently had surgery on my spine so I can't physically do much of it myself. Anyhow my Navigator ran great up until about 2 weeks ago, and now its almost like its skipping or misfiring definitely losing power between 2500-4000 rpms. Or when its below 900 rpms it runs really rough when its in gear, but not all the time. Wasn't throwing any codes at first when I took it to the local dealer. Then about a week later it had a misfire on cylinder 5. So I decided since it is getting near 100k miles I would go ahead and replace all the spark plugs and the coil packs. So that fixed that code. But didn't fix the original issue. It started throwing 2 other codes P0022 and P0012 Intake camshaft position timing over retarded (bank 1 &2). So I did what the guys at the dealership as well as Autozone said and replaced the camshaft sensors even though when I tested them like my book said they seemed to be working fine. Still didn't fix the problem. Next they recommended the Throttle positioning sensor, still didn't fix it. I've cleaned the MAF and have no vacuum leaks, but it still does it. I had the fuel system cleaned also, and still the same thing happens, but its only when it downshifts under acceleration to pass someone or towing type situation or when i'm driving really slow in a parking lot or something. I'm just wondering if anyone else may have a clue what all this could be cause its becoming an expensive guessing game when I take it to the dealership or a shop.... I really appreciate any suggestions or help anyone can give, Thanks in advance!!

 

It has the 5.4L by the way if that matters.... I've been reading around on this site for about a week now and seen a few others that were similar, but didn't wanna jack anyones thread for my first time posting here, but all the advice given in the other threads it seems we've tried it and still has the same result. Anyhow hopefully someone can offer some help.

 

This is just a guess. I would not rely on the oil pressure gage but put a direct reading oil pressure gage on, just for test purposes, and verify that you really have 20 psi or better at an idle. From what I have read the cam phasers are controlled by the oil pressure and if it is not sufficient the cams will be improperly phased, either advanced or retarded. To learn more on the subject I suggest that you go through some of the posts in the 4.6 and 5.4 engine forum.

 

Thanks for the idea!! I'll give it a try as soon as I find an oil pressure gauge. Anything is worth a try I guess. I've read through a few of the other topics already trying to figure it out, but never really thought about it being an oil pressure issue either. I'll hopefully be able to find one in a few hours and get back to ya. I appreciate any suggestions though

 

Well it I thought I had it fixed after I had the oil pressure and all checked, but apparently not.... I did go and buy an oil pressure gauge today, but can't find in the repair manual where the oil pressure sensor/switch is located. And like I said before since I just had neck surgery I can't exactly climb around under it to find it myself. So i was hoping and wondering if some of you guys could steer me in the right direction so I can install one that way I will be able to tell exactly what the oil pressure is all all times. It did clear up some before when I replaced the fuel filter and all for about a week also, but now it almost feels like i'm chasing my tail with this thing cause nothing makes sense. Anyhow thanks again for any help or advice.

 

The oil pressure sender is on the driver side of the engine in front of the oil filter.

 

Thank you!! I'll see if I can get it all hooked up today then....

 

While you are under there look closely at the aluminum housing that holds the filter on the engine for leaks/seepage. If there is any, tightening the bolts rarely help but a new gasket is a fix that is not too hard to do. That is a common leak/drip location on the Modular engines.

 

What did you find on your problem?

 

I think he has gone away so we might never know.

 

Thanks, Has anyone else replaced the cam phasers and fixed the problem?

 

You need to check these areas for a better solution:
a)An incorrect valve clearance may cause hesitation.
b)Fouled spark plugs may cause hesitation.
c)Make sure the automatic choke is working properly (wire to the coil attached, choke properly adjusted and opens the butterfly valve in the top of the carburetor as the engine warms up).
d)Make sure the idle cut-off valve is properly seated, electrically connected and working. Test the valve by removing the wire, turning on the key, and touching the wire back to the connector on the valve. You should hear a distinct "clicking" sound; no "click" means "replace."
e)If the engine stumbles when you open the throttle, they problem could lie with the accelerator pump, or it could mean that either the main jet or the idle just is too small. Check to make sure that the pump delivery tube is pointed directly down the carburetor throat, and check to make sure that it discharges fuel when the throttle are is pulled down sharply.

Try to properly check these highlighted areas of your car if it is troubleshooted then its better to contact the company for a better solution.

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Badevaerelse , Toiletter , Belysning, Spa bad , Lamper

 

That might be good information if our trucks had carburettors, I don't think any of it applies to most vehicles built after the mid '80s. But... in any case welcome to the FTE.

 

I think I smell spam

 

That was it, i replaced the choke pull off on the carb, advanced the timing and flipped the air cleaner lid and it runs great. Oh wait that was on my 72 pontiac lemans when i was 18!