1992 3.1Lumina Euro misfire under Acceleraton

[TheBandit_1986]

Hey guys

Im new to this forum and well Im havin some issues with 3.1.  Now, when I have the car in park or neutral the engine revs up just fine nut when Im driving it how ever it starts to misfire and has no power shaking all that fun jazs it doesnt start till about 2500 rpm and its starts under hard acceleration.  Now the part that I thought was odd is I jacked the car up put it in gear and no misfiring or anything like that any Ideas on what it could be?  

[Go4DaMo]

Could you consistently drive it uphill to avoid problems?

[Psych0matt]

Start by Checking your injectors as well as spark plugs and wires.

[TheBandit_1986]

ok i will do that today and let you know what I come up with 

[Padgett]

Most common cause I see is weak secondary ignition. Is worst under a heavy load and low rpm. Light load will be fine.

[TheBandit_1986]

yea thats what it seems like so your saying a coil could be bad? 

[TheBandit_1986]

I figured I should list the parts that are new due to the fact it may eliminated a few things the problem could be 

fuel pump and filter 

sparks plugs and wires 

idle control valve 

throttle position sensor 

crankshaft position sensor

ignition control module

O2 sensor

Map sensors

Ive gone over the vacum lines they all check out

there is no arcing from the spark plug wires I check that out

also I cleaned the egr out 

 

I also did notice that the idle is jumping around a lot the car normally idles at around 600rpm and every so often it drops but it returns to normal rpm and

it tends to idle a little rough as well.  The problem seems to be intermittent as well the lack of power and shuttering seems come and go at various rpm sometimes on accelerating from a dead stop to mid and high rpm.  Im honestly stumped on this one 

[Padgett]

That erratic idle is usually a dirty IAC. Should be a simple fix. See here.

 

That has the individual coils (Delco ignition) ? I have seen failing ones act like anything and miss at any speed (but often temperature related).

 

Erratic nature can also be a failing fuel pump/clogged filter, best to check with a gauge on the fuel rail.

[TheBandit_1986]

yea I was planning on it this weekend and the issue is temp related and yea it has individual coils.  I doubt its the fuel pump thats not even a year old but I will check the fuel pressure at the rail this weekend.  I also did change the fuel filter over this last weekend as of right now Im leaning more towards a coil at the moment just due to the fact it has plenty of power cold but when it gets warm the issue gets even worse.

[Padgett]

See here. Not very precise but you get the idea. Think the primaries for a Delco should be .3-.5 ohm and secondaries 7-11K ohms.

[White93z34]

I'm going to go ahead and move this to powertrain since its more of a technical discussion then anything.

[worb4me]

I had the opposite problem once. 1992 Euro 3.4, accelerated fine on the highway, but would "fluctuate"

If you revved the engine while parked.

[pitzel]

Plugs gapped properly?  I had a misfire under load that went away, but the plugs were way, way out of spec.  (ie: 0.08 inches when the spec was less than half that!)

[Padgett]

With a Delco ignition I usually gap Rapidfire #14s at .060" in 3800s. I notice the LQ1 also calls for 14s. Same gap ?