HELP!!! SUPER ROUGH IDLE AND RUNNING UNTIL ALMOST FULL THROTTLE!!!
#1
HELP!!! SUPER ROUGH IDLE AND RUNNING UNTIL ALMOST FULL THROTTLE!!!
I have a 94 Bronco Eddie Bower edition with the 5.8L 351 E4OD 4WD. I aboslutly cannot figure out why the heck it runs the way it does. At idle, when it first starts it runs great for about two minutes, then it starts acting like it's runing on 4 cylinders.. And idles very very low.... When you try to rev it up it's mostly just hesitant and choppy on it's way up the rpm, AND IT's VERY RICH RUNNING. Same thing when driving, it idles rough at a stop light in gear, then as soon as you press the throttle it starts chugging and almost feels like it's missing and running like crap... *** weirdest part**** check engine light comes on and off for about 20 mins of driving, after that it stays on AND when it's held at full throttle, after about a second and a half to two seconds of delay, she comes ALIVE!!! All 8 just blasting away like a friggn monster truck lol.. But anything below about 3/4 throttle it runs HORRIBLE....
Things i've replace/Done since i got it yesterday.
IAC VALVE
MAP SENSOR
FUEL PRESSURE REGULATOR
SPARK PLUGS
SPARK PLUG WIRES (tomorrow)
CLEANED THE INTAKE SYSTEM (Air cleaner, box, & tubbing)
CLEANED ALL THE CARBON AND OIL INSIDE THE INAKE MANIFOLD AND THROTTLE BODY WHERE THE BUTTERFLY VALVES OPEN AND CLOSE
QUESTIONS/SUSPICIONS About what I think it may be..PLEASE HELP!!
1. Is it the O2 Sensor??.. It has a custom exhaust system, with a tinny little pipe connecting the dual down pipes, and the O2 sensor is mounted in the little pipe in between, AND THERE are small holes on either side about an inch or so away from the O2 sensor!!! Would this cause my problem?? Rich running, chugging, jerking???
2. Would the EGR Valve cause this?? Or only lighter symptoms???
3. I'm skeptical about the coil, after screwing with the engine a little i saw THE COIL ITSELF ***Ark*** like itself lol, picture the coil shocking itself JUST once, tho, it was like a quick spark/ shock out of the blue, i can't remember if it was running or not tho.. Regardless, would the coil really cause this much crap???
What else is there!??? What kinda freaky crap am I missing!!??
Low idle, rough, rich, boggy, misfire like, then boom, full throttle
runs great!!!
Please help and Thanks so much!!!
Things i've replace/Done since i got it yesterday.
IAC VALVE
MAP SENSOR
FUEL PRESSURE REGULATOR
SPARK PLUGS
SPARK PLUG WIRES (tomorrow)
CLEANED THE INTAKE SYSTEM (Air cleaner, box, & tubbing)
CLEANED ALL THE CARBON AND OIL INSIDE THE INAKE MANIFOLD AND THROTTLE BODY WHERE THE BUTTERFLY VALVES OPEN AND CLOSE
QUESTIONS/SUSPICIONS About what I think it may be..PLEASE HELP!!
1. Is it the O2 Sensor??.. It has a custom exhaust system, with a tinny little pipe connecting the dual down pipes, and the O2 sensor is mounted in the little pipe in between, AND THERE are small holes on either side about an inch or so away from the O2 sensor!!! Would this cause my problem?? Rich running, chugging, jerking???
2. Would the EGR Valve cause this?? Or only lighter symptoms???
3. I'm skeptical about the coil, after screwing with the engine a little i saw THE COIL ITSELF ***Ark*** like itself lol, picture the coil shocking itself JUST once, tho, it was like a quick spark/ shock out of the blue, i can't remember if it was running or not tho.. Regardless, would the coil really cause this much crap???
What else is there!??? What kinda freaky crap am I missing!!??
Low idle, rough, rich, boggy, misfire like, then boom, full throttle
runs great!!!
Please help and Thanks so much!!!
#5
Join Date: Jun 2006
Location: Ottawa, Ontario
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There cannot be any leaks in the exhaust system upstream of the O2 sensor. Once you get that fixed pull the codes and post them up.. the exact code numbers. Do you plan to keep this truck for a while? It may be worth your while to buy a code reader for it, the Equus/Inova 3145 is the one to get and it's not expensive.
#6
I didn't see you mention anything about the throttle position sensor. Take a look at that too and make sure that isn't contributing to anything.
Since you are replacing lots of things at once, never rule out the fact that a new part could be bad out of the box and that really can throw you off.
Check those vacuum lines.
You can do an engine running test and see if it gives any codes.
Since you are replacing lots of things at once, never rule out the fact that a new part could be bad out of the box and that really can throw you off.
Check those vacuum lines.
You can do an engine running test and see if it gives any codes.
#7
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