A stretched timing chain can cause all of the issues you are having. A bad timing chain can cause it run rough, it can cause lower compression (blowby, smoke in the engine block), and a less complete burn in the cylinders, which leads to excessive exhaust gases, then gunk (plugged EGR system) etc... If you want it to run like a top then a timing chain replacement should be the first step anyway. Most people never replace them and just keep running the vehicle until it feels like a piece of junk, then they sell them, and we DIYers end up with them. I fit where my truck, I would replace the timing chain and flush the motor with seafoam, then compression test to see how good your cylinders and valves are. If the compression is still bad, then replace the rings and lap the valves. While you are there you can clean all the crud from the EGR system.

 

Great additonal suggestions yarddogg -- I am going to check those components. What symptoms can a failed TPS produce? I think the first thing I will do is drain the gas tank of all the old gas (now I am told it sat for 3 years!).

 

If it sat for three years, it isn't gasoline anymore. It might burn, but, not very well.

 

I'm not so inclined about the sensors and computers, mechanical is my strong suit. I say make sure it is mechanically sound first, then worry about sensors. And yes, good fuel is essential. Todays fuel with ethanol can crystalize and plug things up, not to mention a fuel tank can collect condensation, there is probably lot's of it in the bottom of your tank. The inside of the tank will sweat during warm to cold spells, then the water becomes trapped under the petroleum. Clean fuel and some injector cleaner might do wonders.

 

Going to be siphoning off all 15 gallons of fuel and starting with some fresh gas + fuel injector cleaner (with PEA and a drier). And you're right ('"if it sat for 3 years it isn't gas any longer."). Making progress though -- new valve cover gaskets in, new cap and rotor (only small amount of play in rotor shaft), new EGR gasket (after cleaning carbon), thoroughly cleaned TB, new air filter (and thoroughly cleaned all the rat poop and nesting that was stuck in the length of the air box and snorkle tubing). Found a new TPS for super cheap (Wells brand) on ebay for only $12 -- will get it ordered. After I run a new tank of gas through, I will be replacing the fuel filter (to let it collect all the crud that is sitting at the bottom of the tank). And then I will assess the fuel injectors at this point and decide whether or not they need to be replaced.

 

Those cheap TPSes don't work all that well; mark my words, you'll end up ordering a Mopar unit anyway.

If you DO pull the tank - BTW, there's a siphon tap on the 1988 Fuel Pump Hat, or more accurately, down on the frame - PULL the tank, and flush it out.

Don't forget a couple of quarts of 91% rubbing alcohol after washing it out; that'll help get the crud and crap out, and take out any water.

That's a perfect time to replace the pump itself, the rubber back there, and to clean and test the sending unit (the bronze fingers tend to loose a bit of tension, plus the silver coated wiring in the sending unit oxidizes; amazing what some time with a dollar bill as a polishing rag can do!)

RwP

 

That's an important piece of information you just provided me with Ralph -- the bit about siphon access and the bit about the TPS (glad I did not order it yet). Are you saying there is a way to siphon the gas out of the tank without removing it? Is there a siphon block mechanism just beyond the filler neck?

 

I'd have to pull the bed to take a pic - but when you crawl under there, with a BRIGHT light, look for a stub with a rubber cap on it. It goes down inside the cap all the way to the bottom.

Nice idea, IMO.

Let me see if there's a pic in the FSM ...

See the attached PDF. It has a drawing, but shows about where the drain hose is.

I'm not sure you can SIPHON, but you can for sure PUMP it out with a small pump there. I THINK a siphon pump (to start it) will do the job.

RwP

 

Many thanks Ralph. Again, I cannot than you enough for all of your help and pointers -- extremely helpful.