- Joined
- Aug 10, 2014
- Messages
- 503
- Reaction score
- 22
- Points
- 18
- Age
- 31
- Location
- Madison, IN
- Vehicle Year
- 1995
- Make / Model
- Ford Ranger
- Engine Type
- 4.0 V6
- Engine Size
- 4.0L
- Transmission
- Automatic
- 2WD / 4WD
- 2WD
- Tire Size
- 215/70R15
My 1995 4.0 has developed a low rough idle. Warm or cold, she idles at 250-500rpm and very roughly, often times failing to start. Give it some gas, she will start/run but with reduced power. No CEL either.
I originally suspected fuel pressure trouble, which was found, and after replacing the fuel filter, fuel pump/sock, and pressure regulator I was able to get to the specified 30-40psi (at least from what I have measured during dead head and attempted idle tests). However, the issue still persists.
I cleaned out the throttle body, which was FULL of carbon. Slightly better, but still no good.
Disconnecting the EGR valve's vacuum line did nothing.
I did some scanning with my bluetooth scanner, and found that the upstream O2 sensors are reading lean and the short term fuel trim being around +35-37%. Since it's both sensors, I'm thinking that I am running very lean and not that both sensors went bad at once.
No obvious vaccuum leaks; I was getting pulsed vacuum at the EGR valve control hose (so it is pulling vaccuum).
At this point I'm stumped... suggestions?
I originally suspected fuel pressure trouble, which was found, and after replacing the fuel filter, fuel pump/sock, and pressure regulator I was able to get to the specified 30-40psi (at least from what I have measured during dead head and attempted idle tests). However, the issue still persists.
I cleaned out the throttle body, which was FULL of carbon. Slightly better, but still no good.
Disconnecting the EGR valve's vacuum line did nothing.
I did some scanning with my bluetooth scanner, and found that the upstream O2 sensors are reading lean and the short term fuel trim being around +35-37%. Since it's both sensors, I'm thinking that I am running very lean and not that both sensors went bad at once.
No obvious vaccuum leaks; I was getting pulsed vacuum at the EGR valve control hose (so it is pulling vaccuum).
At this point I'm stumped... suggestions?