I am getting black smoke on light to heavey acceleration. On light acceleration it is jerking a little. It has never stalled. It starts very good. Descent power, but it did shift on a hill in cruse, never done that before. Turbo vac is all good. Milage is still @ 16 at 2000rpm. I have ran cleaner through it. Could it be the IP, PMD, or possibly a plugged cat? It has 104000mi, all original. Its due for something to go. What am I looking for here?

Fuel filter for jerking symptoms, air filter for black smoke and jerking.


Low quality fuel will cause both symptoms.


Then check EGR system for leaking exhaust into the intake - that's the device topcenter of the upper intake plenum.


Take a trip at sustained hiway speeds - about 50mi should burn the soot out of the oxidizing converter\soot trap, mostly called the 'cat'. Edited by: gmctd

what 'cleaner' did you run through it? No 'cleaner' on the market is for a diesel fuel system, I dont care what the bottle says. The two things you want in an Additive are lubricity and cetane improvers, and the two you don't are anything to do with 'clean' or 'removes water', so whatever you have left in your bottle of 'cleaner' throw it out.


Now, I would replace both fuel/air filters, while your at it get some real additive to put in and then see how she does. Down shifted on a hill with cruise, excellent, your cruise is working. How much of a bucking/jerking are we talking about? is it like the engine just dead misses once, or is it dead for a few strokes, or does it just kind of wimp out for a few seconds and kick in. None of these problems indicate a problem with the cat, if that were the problem you'd have symtpoms like low boost/ overheating/ black smoke and then would be constant. Does your speedometer cut out when it happens? if your speed sensor (VSS) has a problem then your tranny will be the cause of your jerk.Edited by: Texas Diesel Guy

The fuel filters are new and the air is clean looking. Bought the pickup 10 months ago, not sure how new. In town is when younotice the jerking. It is a very light jerking. It starts at slight acceleration, and I can accelerate through it to a smooth running. The speedometer is steady as is the tach. When it "jerks", it is also smoking. That is when I noticing it smokeing the most. I will change the air filter and go from there. Thanks for the help.

Did all that stuf, new fuel and air filter, cleaned battery terminals, ran two tanks of fuel through it, lift pump is new w/ good pressure. It is still trowing a little smoke on slight acceleration w/ the "jerking" and then clears up on harder throttle.

One more thing. Took all A1 stuff off awhile ago. Still original PMD and pump. 105000 miles

To me, if the problem could be pointed towards the pump, sounds like it could be your Transfer Pressure Regulator piston is sticking. Or, it could be just your transfer pump itself getting a little weak. When the blades, spring band and liner start to get a little wear on them, the band will not be able to hold the blades tight against the liner at low speeds, causing weak/erratic transfer pressure which is used to fill the pumping plungers and to control advance movement. This would also follow your 'mat it and it goes away' because at higher RPMs, centrifugal force holds the blades out against the liner, bringing up Trans Pres. Could be one of those or a lot of other things...advance piston worn/binding, accumulator piston/spring damaged/broken. If the Pump and Injectors are original...which is extremely unlikely, they're due, best to do it all at once, I'd say, saves you on labor too. Injectors will no doubt have worn out valves in them, opening pressure will be way low, poor chatter and atomization at a minimum with that many miles. If you do take it in for pump and injectors, make sure the leave those EGR plates in the Intake Manifold Gaskets for you too.

Thanks for the info. I bought the truck w/90,000 on it. The previous owner reassures me nothing had been done w/ it and he had it from 58,000 mi. The fuel transfer pump is new. This is why it leads me to thinking of injector pump or pmd. Is this not how it should act if they were to go out?

You could have injectors that need to be changed, if fuel filter and other suggestions don't help.

TDG,
I read at DAS that the advance piston scourss it's housing.
This is the first time anyone's ever mentioned it on here.
What's the poop?

The advance piston will undoubtedly recieve some wear over time, it is however very well designed in my opinion. Aluminum housing is beefed up with a steel liner, advance piston itself has to have a lot of wear before it will not function properly. Very very rare is it to see the steel liner worn out, usually water is to blame if it is.