stumble/misfire

[d_money1]

i just put a new alternator and fuse in my car, got all the little problems i was having with that worked out, but still having a serious misfire problem. i pulled the plugs, they've got a fair amount of white powder like stuff on them, and some is on the back of the plug, making me think headgasket. The way it drives, it's very erratic, may pull good through most of first gear, and second, usually by the top of second gear it's stumbling real bad. it felt more like it was running out of fuel while it was happening, any opinions or help would be awesome.

 

[matt98eclipse]

White on the tips of the spark plugs normally means lean conditions. You may be running to lean on top end causing you to knock witch means timing being pulled. Are you useing anything to tune?

 

[NB4G63T]

Put a set of plugs in it and gap .028, also a set of wires and see where that gets you. It's likely the problem

 

[super97gst]

i just put a new alternator and fuse in my car, got all the little problems i was having with that worked out, but still having a serious misfire problem. i pulled the plugs, they've got a fair amount of white powder like stuff on them, and some is on the back of the plug, making me think headgasket. The way it drives, it's very erratic, may pull good through most of first gear, and second, usually by the top of second gear it's stumbling real bad. it felt more like it was running out of fuel while it was happening, any opinions or help would be awesome.

What does the insulator look like on the plugs you pulled out?? A white covered electrode means the engine is running too hot. But the insulators will usually be blistered and there will be very little deposits of any kind on it. What type of plugs are running?? If you're not already you need to run NGK BPR6ES plugs. Also, this plug condition can also be caused by vaccuum leaks from the intake manifold. The reason your car isn't hesitating much until later in 2nd gear is because the motor doesn't have much load on it until then. To check if your headgasket is good check the oil for coolant and the coolant for oil. If there's nothing there that's not supposed to be, the headgasket is good.

 

[d_money1]

i haven't come to any conclusions about this stumble, i re-gapped my plugs, and it helped at idle a little bit, but it still searches for idle continuously, and when it's KOEOff the idle air control is constantly working, if i unplug it with the engine running it doesn't change the engine idling up and down. under load it sparatically cuts out, i dunno if it's hitting fuel cut from a boost leak or if i have problems other places. How do i properly test the MAF? My tps is going bad too i believe, i had to max it out to get it close to the .9k ohms of res., i got it down to the .98 range, but i can't get it any closer. Any guidance would be appreciated.
Neil

 

[97GSTAUTO]

I would start by checking for boost leaks and go from their. Esp if you are having idle surge.

 

[TheWanderer]

If it were my problem, I would say TPS and Mas together. Had the same problem on my 96 elantra 2.0... Replaced the TPS, ran fine for awhile, then the mas threw a cel and i had to replace it. Did the exact same thing you are describing.

I have an extra TPS or 2 laying around if from a 91 and a 92 GS you are interested. As far as I know the GS and the GSX tps is the same... Both tested fine on my car. PM me and let me know, I can ship it out for you.

EDIT: I may even have an extra mas laying around, hafta look.

 

[d_money1]

so, i've posted like 4 different problems in the last couple months, and the car is still not back on the road. had a boost leak at the TB shaft...got it fixed, car ran, kinda crappy, but was driveable, as time went on, it slowly went back to not driveable...found leaks at the injector insulators, replaced those and the uppers, and then the upper orings started leaking, finally got the correct ones from the dealer and now that it holds air (don't know how much boost, but no "hearable" leaks) but still runs terrible, it will idle fine when i unplug the maf. I've tested the tps, and set it by voltage, tested the maf once following instructions on here that i found. I checked base timing. Compression is good...i know the biggest thing right now is that i don't have a boost gauge to see how much of the air is bleeding off...but anybody have any other ideas at all that may point me in a different direction for atleast some things to check out while i'm waiting on my new boost gauge to arrive?

 

[d_money1]

so, i've posted like 4 different problems in the last couple months, and the car is still not back on the road. had a boost leak at the TB shaft...got it fixed, car ran, kinda crappy, but was driveable, as time went on, it slowly went back to not driveable...found leaks at the injector insulators, replaced those and the uppers, and then the upper orings started leaking, finally got the correct ones from the dealer and now that it holds air (don't know how much boost, but no "hearable" leaks) but still runs terrible, it will idle fine when i unplug the maf. I've tested the tps, and set it by voltage, tested the maf once following instructions on here that i found. I checked base timing. Compression is good...i know the biggest thing right now is that i don't have a boost gauge to see how much of the air is bleeding off...but anybody have any other ideas at all that may point me in a different direction for atleast some things to check out while i'm waiting on my new boost gauge to arrive?

 

[Defiant]

Do not keep starting posts about the same issue. If we can't help you, it's time to pay a mechanic.