2007-04-14 01:15:14 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ Pontiac
New plugs and wires, also replaced fuel filter and removed intake to replace valve lifters, Smoke tested for vac leaks, none found. short and long term at maximum + readings. Off of idle runs great.
2007-04-14 01:27:34 · update #1
A bad O2 sensor will give you crappy fuel mileage.
Might also be the distributor causing the misfire code.
2007-04-14 01:21:19 · answer #1 · answered by Just me again, Do I know you ?!? 3 · 0⤊ 0⤋
I'm guessing it's an OBDII vehicle you're referring to, since you're mentioned fuel trims being positive.
You have a lean condition, my friend. That's your primary problem. You should inspect the following componants:
1. Fuel filter. A plugged fuel filter will cause a lean condition.
2. Fuel pump. A weak fuel pump will also cause a lean condition. Checking fuel pressure at the rail port is easiest.
3. MAF sensor. A contaminated MAF sensor wire will cause strange readings, and could contribute to a lean or a rich condition. (Most likely caused by an oil-impregnated air filter, like a K&N...)
One way to check for sure to see if the O2 sensor is working well enough is to richen the air/fuel mixture up manually. Spray some throttle body cleaner into the intake (downstream of the MAF sensor) and watch the O2 readings.
If it runs well at WOT but not at idle, I'd check your spark plugs, the IAC, and the MAF sensor.
2007-04-15 11:59:48 · answer #2 · answered by Kent W 2 · 1⤊ 0⤋
No usually. A misfire at idle only suggests either a small vacuum leak or excessive cylinder leakage possibly coused by a valve not sealing.
With the vehicle at idle take a can of choke cleaner and spray around the intake manifold and see if it makes the engine run different. You will know when you found a leak as the engine will surge. be careful to keep away from plug wires. You don't want a fire!
2007-04-14 01:21:07 · answer #3 · answered by Delphi 4 · 1⤊ 0⤋
Not usually, but I have seen it. To be sure, unplug the sensor and see if that makes the miss go away. If it doesn't that isn't the problem. Make sure the coils are outputting enough spark and the fuel pressure is correct. Have you made sure there is no updated program for a complaint such as this? There is also a chance you have a bad gas situation as winter gas can and does cause lots of driveability problems in the spring. Be sure the plug wires and plugs are good as I've seen plenty of problems with even new ones. I would also suggest a power flush of your injectors as this causes tons of problems with idle misses. Good luck.
2007-04-14 12:20:49 · answer #4 · answered by Deano 7 · 0⤊ 0⤋
On my old Pontiac, replacing the valve meant the idle speed became very extreme for about 3 minutes, then because the computer began adjusting the pintle, the speed got here down... So, enable it run for a minimum of a couple of minutes to allow the computer to move the pintle...if after numerous minutes it isn't dropping the idle, the recent valve is probably defective.
2016-11-23 19:07:52 · answer #5 · answered by Anonymous · 0⤊ 0⤋
the o2 sensor, just helps the on board computer, adjust and keep the fuel/ air mixture correct at set by factory.
the misfire at idle, is a plug going bad, plug wire momently breaking down
2007-04-14 01:20:23 · answer #6 · answered by duster 6 · 0⤊ 0⤋
The answer is no. You should check the Idle Air Control Valve. This is causing your problems more than likely.
2007-04-14 03:51:12 · answer #7 · answered by Anonymous · 0⤊ 1⤋