Yep, sure do. These days they're essentially 100,000 mile parts. Once upon a time they were 60,000 mile parts and lots of vehicles were programmed to set the Check Engine light at 60,000 to force the issue. Nowadays we just have to know what a failure looks like, and/or replace them before they fail completely. Once you know what to look for, you can spot that closed loop transition stumble and buy the part knowing you'll need it soon.

 

Everything else I have tried short of pulling the heads has failed.

Although, taking a paint spray gun and then filling it up with boiling hot distilled water to blast into the engine as the engine ran did improve drivability when in the driveway. Amazing thing about that was the vaporization effect on the boiling hot distilled water; Water came out cool to the touch (no noticeable heat carried through water under).
proper vaporization technique.

Things attempted without benefit: Removal of Catalytic converter, Disconnection of O2 sensor to run in open loop, E85 fuel with approximately 95-100 octane to eliminate predetonation instead of the original 91 octane gasoline with octane booster i tried using beforehand, new timing chain, adjustment of the distributor to syncronize the fuel timing.

This problem apparently is a misfire; diagnosing a misfire can be seen here and is the direction I am currently heading towards since my Check engine light suggested a lean mixture and also due to my truck being able to idle yet not drive under load as if starved for fuel or predetonating. Higher octane fuel has no effect so I'm led to believe the engine is starving for fuel...


Alternative solution to replacing Fuel Injectors can be seen here( ).

Otherwise Oreilly has Fuel Injectors for $47.99 minus $12.00 for a total of $34.99 each thanks to their price match guarantee in competition with autozone.

Update will continue soon...

 

[quote=Slomojo;2883175]Everything else I have tried short of pulling the heads has failed.

Not to say that the heads don't need replacing--Magnum heads are prone to cracking internally within the cooling channels--but I just replaced my heads and components (lifters, arms, pushrods, valves, springs, etc.) and noticed that the intermittent idling problem remains. On the other hand, after the head replacement my intermittent #7 misfire has yet to reappear.

Alternative solution to replacing Fuel Injectors can be seen here( ).


Otherwise Oreilly has Fuel Injectors for $47.99 minus $12.00 for a total of $34.99 each thanks to their price match guarantee in competition with autozone.

I replaced my injectors with a very affordable eBay set, and while I appreciated the peace of mind of replacing injectors at 175,000 miles they did not do the trick either.

Had I not already replaced the cat, multiple O2 sensors, and multiple IACs I would still look in that area. As it is I'm waiting on a set of Delphi sensors to arrive from Amazon this week.

I am going to look up IAC adjustment this evening as one of the IACs I bought from Autozone had instructions for adjusting the pintle. But the dealership one that I currently use went into the throttle body without any adjustments.

I am certain that my plenum is fixed as I no longer experience oil consumption, pinging, or valve rattle since replacing the plenum pan and gasket with the thicker Hughes aluminum plate and steel gasket. There was no evidence of leakage after 40,000 miles when we pulled the manifold to get to the heads last month.

At this point I still suspect an intermittent short somewhere within the O2 sensor harness itself. I believe it's a 5V circuit along which several crucial emission components run. Unfortunately, electrical diagnosis is probably my weakest "skill" when attempting truck repairs.

Best of luck: once I get the O2 sensors in (and reset the PCM) I'll know in pretty short order whether this fixed the problem. But I've done it [replaced the O2 sensors] three times before with no noticeable improvement...

 

I had this issue...was very intermitent...turns out my fuel pump was failing. I figured it out when I was driving when it started to do that I would sway the truck side to side (erratic steering) and the engine would smooth out for a second. It turns out the motor in the fuel pump would get hot and start to sieze, and not be able to keep up with proper fuel flow. Not saying this is your issue, but I had exact same symptoms. When it does it, try banging the fuel tank to see if it goes away.

 

First thing I tried was a new fuel pump... $200 later and I still had the same problem. It's 2 o'clock in the morning right now and I am doing my plenum gasket... Found a serious pool of oil in the intake manifold so I've got to take care of that before my issue is solved. Another thing going on is possible electrical issues as highlighted by Wjamesbass...

If The plenum and some new spark plugs don't help solve this issue I'll being looking for electrical issues next.

Recently I found a shorted out set of wires coming from the O2 sensor. I repaired the short but it's certainly possible that the short has traveled towards the engine and thus continues to exist at some other point in the wiring harness.

Fortunately, as difficult as tracing bad wiring is on these trucks, pulling the harness completely is not. I have pulled the harness on this truck before and there really is not much too it. Tracing the short with the harness removed would be a breeze and worst case scenario, I can simply find a junkyard harness and throw that one in there if I suspect a serious short in the harness...

More to come as I go along.

 

Its only 7 o'clock in the morning and I am all done cleaning up. Serpentine belt needs to be reattached and I need some coolant in the motor but she should be ready to go; I hope...

I'm signing out, keep the ideas flowing on what'll help and I'll keep wrenching.

 

Good luck Slomojo! I am suffering similar problems that people are on here -so Im not "jacking" the thread. I agree with the electrical problem, Im thinking of going to the salvadge yard and buying another wiring harness myself. I tried switching computers and I still get the same code-which is #27 fault in the fuel injection circuit. Ive replaced the injectors, connectors, and redid the wiring from the main harness to the injectors on both sides of the engine. Im about to give up-lolol

 

The plenum gasket is all done, new plugs have been installed, and the engine still won't start. After battery was removed all trouble codes have been erased, yet I found a way around that.

Holding the Odometer Trip Meter Reset Button while turning the Ignition Switch to the accessory position and then to the OFF Position in a sequence of three times. This was done until on the third time I left the ignition switch in the ON Position and I released the Odometer Reset Button. From there I was able to have the engine computer run a diagnostic scan for trouble codes to help me identify what problem I am having which was preventing my vehicle from starting or running properly.

After testing for codes, I came up with two trouble codes: 1282, and 320.

1282 = Fuel Pump Relay Malfunction.

320 = Ignition/Distributor Engine Speed Input Circuit Malfunction; No Crank Reference Signal At PCM.

Crankshaft sensor shares the same ground as on the O2 sensor (Black Blue Wire) that I found shorted out, There were four total Black Blue Wires stemming from the wiring harness going who knows where other then the Crank sensor as well as the O2 Sensor...

Crankshaft Sensor as well as the Camshaft Sensor both determine the timing on this vehicle, thus what was apparent from the get go is that my timing is off the wall due to the signals being generated my my cam and crank sensors inputs or outputs being too high or low.

From here on out, I am focusing in on electrical issues. I will be pulling my harness and searching for shorts that stem from my Pre-Catalytic converter O2 Sensor. That is where I suspect all of this began.

Yahoo for 5 weeks of a non operational vehicle and $400.00 in parts thus far!

 

Don't overlook the easy things. Make sure you connected the control wires to the coil. Dont' ask what makes me think of that one....

 

Are you talking about the black wire and the green with the red stripe colored wire going into the coil? If that's what you are referring to, it's connected. I also tried swapping out the PCM for no apparent beneficial results.

More and more points to the harness, and no longer can I avoid dealing with that.