Hi Guys,

i have the problem that my Bonne has a realy rough idle, it jumps between 500 and 800 rpm so the whole car is swinging when the engine idles that rough.

it'* not ever, but in the last time, nearly ever. it'* in every Gear and it stops as soon as i hit the gas, everything works normal. i can drive and everything, it even is realy powerfull, if i drive it WOT the car runs like chased by the devil.

but when i come to a stop liht or even i'm parking anywhere the engine begins to idle rough and it'* anoying.

It'* both when the engine is cold or hot, that doesn't matter.

I checked for vacuumleaks and realy found one and so i replaced all vacuum connectors and checked again, i don't have a vacuum leak anymore now.

also it doesn't have any effect if i pull the maf or not.

I scaned the car with TunerPro and i have no troublecodes (only 58....) the only thing i've seen is the it shows that the car ever runs lean and my BLM is on 150, the INT is on 128 like it should, but when i'm driving the INT goes up to 182, so this isn't good at all.

i also think that my O2 sensor is gone, because it ever shows lean, and even in closed loop it shows around 100mv. other i know should move between 300 and 800 ever. but mine doesn't do that, but the O2 Sensor only effects in closed loop, so why do it idle that rough in Open Loop when the engine is cold? and could it maybe be that my O2 Sensor isn't bad but my engine is realy running lean all the time?

I Ohm checked my Coils in hot and cold condition and they are perfect, also my Fuel Injectors and i havent had any Gas smell or even Gas in my vacuum line on the Fuel Pressure Regulator. My Plugs and Cables are new and also i don't have anymore Ground issues. I don't know where i should start now with the search, it'* anoying. realy.

BUT, and here my other question:

when the car stand over night i don't have anymore fuel pressure i can push the needle but there doesn't come out any fuel. On other cars i tried the same, and they have sit for longer periods and still have a bit pressure on the fuellines.

so what could be the problem here? could this cause all of my problems above?

I hope you can help me figure out what'* wrong.

Thanks in advice

Manni

ps: if someone uses TunerPro, i have 3 saved Records of my problem, so if someone would have a look on it, just let me know.

Start by checking the throttle body, it needs a cleaning. The O2 sensor showing lean tells me a possible exhaust leak between the engine and the 2 sensor.

Hi!

Thanks a lot, but i forgot, the TB is totally cleaned up, also the MAF and the IAC.

but a leak in the exhaust sounds possible.

2 years ago i welded the front manifold in his elbow, the it was cracked, maybe it'* broken again, but i don't hope so.

Could this cause this dammned rough idle and could the O2 sensor be still good? because i've seen that when i have WOT the O2 shows around 850mv.

Thanks again.

Manni

That'* showing lean. Pull the spark plugs and inspect them. Are the a nice light gray or are they dark gray or black? Pull all the plugs and compare them, they should all be about the same color.

I'll do that tomorrow and report than, but have you an idea what'* up with my loosing fuel pressure over night?

You could have a injector sticking open and dripping fuel in the the intake when the engine is off. Do you see any leaks on the floor?

no, nothing besides a few drops of oil in a month from the crankshaft main rear seal... but in this age this is ok i would love to fix it, but it'* so little that it'* not worth it to remove the transmission...

i thought about a sticking injector,too but will there be a visible leak then? could it also be something else like the pump itself or the FPR? or is the injectors the only option?

thanks again for your help! I'm realy appreciative.

Manni

You can check the FPR by smelling the vacuum line, if you smell gas, it'* bad, but I don't suspect that. The fuel pump could be the problem if it'* leaking pressure when sitting.

would it be a big problem if the pump is leaking while it sits? or could i leave it in place and drive with that maybe for years? or do i loose also fuel pressure while driving than?

how big is the deal to change the pump and is there a way to test it in the car?

i will remove the injectors in the next days and put all 6 in glasses over night and have a look if one is leaking.

When you turn the key, let it sit a second or two before starting it, that should prime the fuel system