Straight Six Stumble under load
#1
Straight Six Stumble under load
Hi guys - new here.
I have an 86 F250 with a 91 fuel injected straight six and 4 speed in it. Engine is strong as an ox, but it has developed a massive stumble under load. So bad that I have to shift down to 3rd to gain speed again.
Any ideas? Any help is much appreciated!
I have an 86 F250 with a 91 fuel injected straight six and 4 speed in it. Engine is strong as an ox, but it has developed a massive stumble under load. So bad that I have to shift down to 3rd to gain speed again.
Any ideas? Any help is much appreciated!
#2
Fuel would be my first to investigate. When was the fuel filter last changed. If you have a fuel pressure gauge, check your pressure at the rail. I'm not sure what it should be, but someone else will chime in. Maybe 40-45 psi. Search for Conaski's posts. I believe he posted the number recently.
#3
Many thanks,
I put in a new fuel pump and filter - did not change anything. I did not measure at the rail though...
Also, and this may be normal, there is a pump in the tank and one under the floor rail driver side door. I think the pump under the driver door is supposed to boost the pressure to around 50PSI. Does that sound right?
I put in a new fuel pump and filter - did not change anything. I did not measure at the rail though...
Also, and this may be normal, there is a pump in the tank and one under the floor rail driver side door. I think the pump under the driver door is supposed to boost the pressure to around 50PSI. Does that sound right?
Thread
Thread Starter
Forum
Replies
Last Post
Shawn Paris
1987 - 1996 F150 & Larger F-Series Trucks
12
08-02-2016 10:56 PM
Trapping
1999 - 2003 7.3L Power Stroke Diesel
6
04-26-2011 08:04 PM
DJdemon6696
1987 - 1996 F150 & Larger F-Series Trucks
27
12-02-2007 04:43 PM