I have a 99 SD with 99K on it. I drive it about once a week and last summer it started to bog down while cruising along at 55 mph or so. It felt like it was running out of fuel and the engine would bog down until I got off the pedal and stepped back on the gas. I had the fuel filter replaced and the pump and cleaned the mass air flow sensor. I have a K&N filter that my mechanic says I should take off. Once in a while I will try to start it and it will seem like it cant get a breath - it will start then stall and then catch. I got back to the mechanic to read the check engine light and he said it just shows a problem on the right bank but it could be a number of things. After spending 1000 on the pump and his labor to remove the large fuel tank I am hesitant to guess anymore.

I can haul a tractor and trailer with this truck and she hauls great, seems to do better when the engine is warm. I have noticed she is using some oil now too.

This week while we are in Tahoe at 7,500 ft it would not start (same air feeling) and I pumped and played the gas pedal until finally it caught and got all cylinders to run. I really need to get this fixed as I usually have the family with me and cant be farting around. Any help would be greatly appreciated !

 

Hmm.... There are dozens of possibilities.
You addressed a couple of the more likely culprits in the fuel filter and pump.

Next I would be thinking MAF, then TPS, then IAC valve.
Since you have K&N, the MAF is number one on the list. How long ago did you clean the MAF? Maybe hit it again and make sure the connector is locking on properly.
Isn't there a temp sensor in the intake tract as well? Pull it and clean it.
For the TPS, try disconnecting and re-connecting.

Lastly, remove the IAC and clean it out with carb cleaner.

When were the O2 sensors last replaced? May be time!

After that... hmmm... need more symptoms to give educated guess.

 

K@N filter dirty ? try replacing it.

you said the truck sits around alot, so its possible its gotten filled just from sitting round to long..

but i'd go back to a stock motorcraft filter over using the K@N one thou.

 

Thanks for the input, I think that when I get back home I will put the stock air filter back on and clean the MAF unit. The frustrating this is that the truck runs awesome like on this trip, then does this (luckily near home). It does seem to do it on inclines - which makes me think of a venting issue on the tank or something.

I want to be able to pull a camper trailer with the family and not knowing what is going on is dicey.

 

You said there were codes that made your mechanic say a problem on the right bank.
What were the codes? Is there always a code set when the truck acts up?
Find out what codes are thrown and post them. One would assume that there was an indication of low fuel pressure if your mechanic swapped out the fuel pump?
The system on the 99's has a fuel pressure regulator bolted on to the fuel rail, it is vacuum operated.
Did your mechanic check manifold vacuum, fuel pressure, replace the pcv valve and check the vent hose from the valve to the throttle body for cracks causing possible vacuum leak.
Post up some codes.

 

Well I changed the air cleaner back to stock and clean the MAP with the electronics cleaner I have. I looked into the IAC but it was more than I wanted to deal with and thought I would see what the "clean" air filter would do. The K&N was dirty but when I cleaned and reoiled it - it always seemed to be dirty. We live on a dusty road in and I am thinking it was always passing dirt. I hope I didnt smoke the rings with the grit.

I washed her too - posted some pics - now she needs a polish!

The following was posted and I have some questions re:

Next I would be thinking MAF, then TPS, then IAC valve.
Since you have K&N, the MAF is number one on the list. How long ago did you clean the MAF? Maybe hit it again and make sure the connector is locking on properly.
Isn't there a temp sensor in the intake tract as well? Pull it and clean it.
For the TPS, try disconnecting and re-connecting.

Lastly, remove the IAC and clean it out with carb cleaner.

When were the O2 sensors last replaced? May be time!

I am going to pull the records, but I dont remember changing the O2 sensors. What is the TPS ?
There is another sensor in the intake - maybe the temp sensor mentioned - what should I used to clean it?

I remember seeing a diagram of the various sensors in a post and couldn't find it again today. So clean the IAC with carb cleaner ? okay...

She seemed to run more smoothly than before with better breathing and gained more rpms before shifting. I will drive her a bit to see how this worked.

Thanks Guys..