8.1 Power Loss

[Dirtbags77]

I have a 2006 Sunvoyager with a 8.1, 2100MH Allisonon a 24,000 Workhorse Chasis. Currently at Moab traveling in the West from Fl. I got a check engine light and took it in to a shop at Wells, Nv. Nothing came up on a scan so we had the fuel filter changed. It was a little dirty but not clogged. The problem I had was a loss of power. After the filter change it runs down the road no problem until we get an incline in the mountains. Went up a 5% grade and it dropped to 38mph trying to get up the hill. The temp gauge stays in the middle but the cooling fans run a lot of the time. I have not lost any coolant so I am really trying to figure it out. Our next stop is Albuquerque so any suggestions are appreciated. Also if anyone knows a good shop in Albuquerque, I would be glad to have that info also. Thanks in advance for any assistance.

[ArchHoagland]

Had the same problem intermittently over a year. Changed O2 sensor and fuel filter...no help.

Finally cleaned MAF sensor. Presto all my power was back and no more check engine lights.

So have your MAF sensor cleaned. After that replace your spark plugs and wires.

[wa8yxm]

NO I said two plugs were changed. The went with the two Primary circuits that had been chewed..... Those plugs are rated 100,000 miles by the way.

But yes. by all means check them and replace if needed.. The primary issue on my 8.1 was chewed wires

On the much smaller car it was the air filter.

Fortunatally.. I have some training in the diagnosis area

NOTE: Codes can be "Transiant" there is a program for Android (TORQUE) and a devie you plug into your OBD-II (Purchased sepertaly) and it will display AND LOG all codes.

Also the Mobly device from AT&T or T-Mobile or others will send the codes to your Phone as well,.

[Stealth_Mode]

Like wa8xym said, change the plugs. On our Alaska trip last year, our friends in a '07 Sunova were having performance problems. After he got home , his mechanic changed the plugs and wires and solved the problem. My buddy said in the manual it said to change plugs at 50000 miles. Good luck.

[wa8yxm]

YOu changed the fuel filter.. THe following is a true stories.. I should know (First person)

I pulled out of work (Car not RV) and I could not get it over 45 MPH on the Freeway.. I found a spot where I could and checked the AIR FILTER.

Yup.. New air filter and... I won't tell you how fast it went but the Speed Limit was NOT a problem...

There are two filters

THere are also several other possible issues..... I am an old farm boy and I was driving my RV and something did not sound right to me.. Wife could not hear it but to me... Misfire

Turns out mice had chewed the ignition primary (2 cylinders) i was driving a V-6 instead of a V-8... Some tape, 2 new spark plugs and 100% again.

I noticed a drop in both power and MPG on the trip to the shop.

[A1B00902]

Had same to me ,going up a mountain grade
coach went into limp mode, with the check engine warning light,
it turned out to be the oxygen sensors,
I had been noticed loss of power on my last trip,
Then this time when the engine light came on again
A scan showed the problem
It now runs like a new unit again

[MountainAir05]

fuel pump. Alone with pressure check the volume, It can have pressure, but the volume can be low.

[rgatijnet1]

Things I would suggest checking would be dragging brakes, even if the brake recall was done.
Dragging emergency brake.
Clogged air filter because of water sucked in to the intake horn.
Check air fuel ratio with a scan gauge and see if it is in the 14.6-14.7 range.
Check fuel pressure to see if fuel pump is functioning correctly.