Tater Tot
New Member
- Joined
- Sep 25, 2019
- Messages
- 15
- Reaction score
- 0
- Points
- 1
- Location
- FL
- Vehicle Year
- 1994
- Make / Model
- Ranger
- Transmission
- Automatic
I have a 94 ranger 4.0 2wd. Long time issue. Replaced many sensors. Timing issue? Vacuum leak? Ugh please help.
~112k miles
Symptoms, all in order:
Engine cold start: RPM’s always low at idle when cold. Always starts. Engine starts up fine, revs high for a few seconds and immediately drops idle very low, no tach but engine and truck visibly shakes, seems like it could die at any moment but never does. Exhaust sounds like a putter patter, Engine doesn’t rev up when cold at idle, even worse when a/c is on. Air idle valve is new. TPS, ECT, thermostat, spark plugs and wires, PCV, fuel injectors, upper intake gasket, o2 sensors, crankshaft position sensor, all <2 years old. MAF is 3 years old. Fuel rail pressure is 29 psi. Engine computer battles to regulate rpm, letting idle for a while, sometimes the engine rpm will shoot up randomly, but it tends to just idle super low mostly.
Taking off driving: I have decently loud exhaust, engine misfires while accelerating (muffled misfiring, not bangs or pops), when hot or cold (used to be intermittent misfire, now constant problem whether hot or cold). I live in FL so temp is never that cold.
Still driving: Seems like the engine won’t climb rpms, misfiring (not loud, chokes misfiring). Transmission short shifts, can’t climb rpms.
In 3rd gear, the gear seems long enough, once I reach a certain rpm, the engine springs to life like nothing is wrong. It’s misfires, has no power and won’t go anywhere even when floored and when it hits a certain rpm and everything seems normal and dandy. Sometimes I can’t hit a high enough rpm before it shifts, it seems like, and I can’t accelerate out of the problem. Trans maybe 30-35k miles on it. Transmission seems to work fine.
It’s done this most of the time I’ve had it, 3.5 years. Gotten way worse with my first full summer in hot hot FL.
Cleared all codes today, when misfiring after clearing codes while driving, the only code was 177 (rich left side).
Did check test with Innova for obd-1 immediately after driving. Only codes then were 136 and 172, lean right and lean left.
What the heck is going on?
Vacuum leak- if it is a vacuum leak, it’s not from vacuum hoses. I disconnected and plugged all vacuum lines, unless it’s the fuel pressure regulator leaking (new vacuum line to it). Seems doubtful, the regulator seems fine. Lower intake leak? Upper intake gasket is new. No audible hissing or other vacuum noises. Doesn’t seem to be oil or coolant in gas. Exhaust is clean, no smoke or vapor or anything. No clogged cats.
Why does my engine come to life at a certain rpm like nothing is wrong? Like you would think the engine could die at any moment, never does, then I hit a certain rpm and everything is just as good as it could be.
I’ve noticed as well when I get to 35-45 mph, before it was struggling all the time, the engine has a power jump that starts at higher rpms. Timing issue? PCM - CamshaftPS - motorcraft EDIS 6 (module behind front driver headlight basically).
Why would my truck not be able to accelerate and misfire, even when floored, then seemingly hit a certain RPM, and run amazingly?
~112k miles
Symptoms, all in order:
Engine cold start: RPM’s always low at idle when cold. Always starts. Engine starts up fine, revs high for a few seconds and immediately drops idle very low, no tach but engine and truck visibly shakes, seems like it could die at any moment but never does. Exhaust sounds like a putter patter, Engine doesn’t rev up when cold at idle, even worse when a/c is on. Air idle valve is new. TPS, ECT, thermostat, spark plugs and wires, PCV, fuel injectors, upper intake gasket, o2 sensors, crankshaft position sensor, all <2 years old. MAF is 3 years old. Fuel rail pressure is 29 psi. Engine computer battles to regulate rpm, letting idle for a while, sometimes the engine rpm will shoot up randomly, but it tends to just idle super low mostly.
Taking off driving: I have decently loud exhaust, engine misfires while accelerating (muffled misfiring, not bangs or pops), when hot or cold (used to be intermittent misfire, now constant problem whether hot or cold). I live in FL so temp is never that cold.
Still driving: Seems like the engine won’t climb rpms, misfiring (not loud, chokes misfiring). Transmission short shifts, can’t climb rpms.
In 3rd gear, the gear seems long enough, once I reach a certain rpm, the engine springs to life like nothing is wrong. It’s misfires, has no power and won’t go anywhere even when floored and when it hits a certain rpm and everything seems normal and dandy. Sometimes I can’t hit a high enough rpm before it shifts, it seems like, and I can’t accelerate out of the problem. Trans maybe 30-35k miles on it. Transmission seems to work fine.
It’s done this most of the time I’ve had it, 3.5 years. Gotten way worse with my first full summer in hot hot FL.
Cleared all codes today, when misfiring after clearing codes while driving, the only code was 177 (rich left side).
Did check test with Innova for obd-1 immediately after driving. Only codes then were 136 and 172, lean right and lean left.
What the heck is going on?
Vacuum leak- if it is a vacuum leak, it’s not from vacuum hoses. I disconnected and plugged all vacuum lines, unless it’s the fuel pressure regulator leaking (new vacuum line to it). Seems doubtful, the regulator seems fine. Lower intake leak? Upper intake gasket is new. No audible hissing or other vacuum noises. Doesn’t seem to be oil or coolant in gas. Exhaust is clean, no smoke or vapor or anything. No clogged cats.
Why does my engine come to life at a certain rpm like nothing is wrong? Like you would think the engine could die at any moment, never does, then I hit a certain rpm and everything is just as good as it could be.
I’ve noticed as well when I get to 35-45 mph, before it was struggling all the time, the engine has a power jump that starts at higher rpms. Timing issue? PCM - CamshaftPS - motorcraft EDIS 6 (module behind front driver headlight basically).
Why would my truck not be able to accelerate and misfire, even when floored, then seemingly hit a certain RPM, and run amazingly?