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Lost on stuttering problem

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nickk90

10+ Year Contributor
407
0
Feb 12, 2010
st.louis, Missouri
I'm at a loss with a stuttering and bucking problem with my car. It only happens during cruise/light load conditions. My wideband will spike rich and lean and stumble really bad. WOT no problems at all.

So far I have changed plugs , wires , o2 sensor and cleaned my MAF.

NGK brp6s gapped to .028 and NGK wires

I had a Bosch o2 sensor and saw a lot off people had problems with them so I swapped it out for a Denso

My coil pack checks out fine

Right now I think it has to be my MAF but I also read somewhere that a dirty EGR valve could cause there symptoms . My car was burning alot of oil form bad valve stem seals but they are now replaces so I imagine that could of cause a lot of build up in the ERG valve.

Any opinions on other things to check out ? I'm at a lose

No one has any ideas or suggestions?
 
Did all the same 2 weeks ago. Kept the Bosch. Deleted egr and emissions in hopes. Car still sputters at 60 between 2500-3000 cruising. Shop that rebuilt tranny says its a bad tcu causing it to try and shift there. TCU not under warranty. I suspect ECU. In another car i had, i replaced cables from battery to fuse box, starter and alternator with 4 ga amp wiring cabling and problem solved.

extra info....- it starts as a random misfire and becomes multiple/second hesitations. Any faster stuttering and it would be a vibration like spurts of no power.
 
I have a ecu im sending to ecmlink next week or so to get chipped and v3lite.
my car is a 5 speed so no tcu.
Its worse the warmer it is outside as well.

I check the injectors with a multi meter and they checked out fine and also put a screwdiver to them and they are opening and closing .

I dont wanna just start throwin parts at it until it goes away thats why i havnt done a erg block off or replaced the maf yet
 
I have a ecu im sending to ecmlink next week or so to get chipped and v3lite.
my car is a 5 speed so no tcu.
Its worse the warmer it is outside as well.

I check the injectors with a multi meter and they checked out fine and also put a screwdiver to them and they are opening and closing .

I dont wanna just start throwin parts at it until it goes away thats why i havnt done a erg block off or replaced the maf yet

I had this EXACT same problem with my first Talon. Never was able to fix it, but I suspected my fuel pump or the wiring going to it since the sputtering would stop if I tapped the top of the unit with the handle of a screwdriver (back seat was off because I was that desperate, LOL).
 
I had this EXACT same problem with my first Talon. Never was able to fix it, but I suspected my fuel pump or the wiring going to it since the sputtering would stop if I tapped the top of the unit with the handle of a screwdriver (back seat was off because I was that desperate, LOL).

I have a wally 255 sitting on my shelf of parts. Looks like thats going in alone with my Koni Yellows this weekend
 
Checked alternator output and belt deflection? My belt is a bit loose. I'm gonna try in a couole of hours. Does sound like its a spark issue though. I'm using duralast wires. Maybe they're not good even though new. Also, my valve cover has a slihht crack and pools a bit of oil on occasion. When cleaned off plug boot, all is good. I had ps fluid leak on alternator for about a week. But autozone says it checks out.

Boost leaks will do it too. When warm, cracks in hoses are bigger. When cold, hoses constrict and can seal better.
 
Checked alternator output and belt deflection? My belt is a bit loose. I'm gonna try in a couole of hours. Does sound like its a spark issue though. I'm using duralast wires. Maybe they're not good even though new. Also, my valve cover has a slihht crack and pools a bit of oil on occasion. When cleaned off plug boot, all is good. I had ps fluid leak on alternator for about a week. But autozone says it checks out.

Boost leaks will do it too. When warm, cracks in hoses are bigger. When cold, hoses constrict and can seal better.

Alt output is fine. New crank pulley and belts a few weeks ago.

Coil pack checked out NGK wires didn't help new plugs didn't help. Those were the 1st 3 things I checked.

The only boost leak I have is the BISS screw. Its not a very big leak and i cant really change it without something to log ICS value.


Im really leaning on my MAF because the warmer the weather the worse it is.

Could a bad knock sensor also cause this?
 
I'm at a loss with a stuttering and bucking problem with my car. It only happens during cruise/light load conditions. My wideband will spike rich and lean and stumble really bad. WOT no problems at all.

So far I have changed plugs , wires , o2 sensor and cleaned my MAF.

NGK brp6s gapped to .028 and NGK wires

I had a Bosch o2 sensor and saw a lot off people had problems with them so I swapped it out for a Denso

My coil pack checks out fine

Right now I think it has to be my MAF but I also read somewhere that a dirty EGR valve could cause there symptoms . My car was burning alot of oil form bad valve stem seals but they are now replaces so I imagine that could of cause a lot of build up in the ERG valve.

Any opinions on other things to check out ? I'm at a lose

No one has any ideas or suggestions?

I highly doubt its your EGR. At cruising speed the egr opens which it is suppose to do, and at WOT its shut. Now if your having idle problems then yes you could check the ecu to make sure its not stuck open, even just a little bit will cause the car to idle rough. The wideband suppose to cycle rich to lean so i dont think thats an issue to be concerned with either. First thing popped in my head was the CAS. It could jus be a lil jumpy, i'd swap it for a known working one and see if happens.
 
I highly doubt its your EGR. At cruising speed the egr opens which it is suppose to do, and at WOT its shut. Now if your having idle problems then yes you could check the ecu to make sure its not stuck open, even just a little bit will cause the car to idle rough. The wideband suppose to cycle rich to lean so i dont think thats an issue to be concerned with either. First thing popped in my head was the CAS. It could jus be a lil jumpy, i'd swap it for a known working one and see if happens.

The wideband make a drastic spike as it bucks. Like 16.5:1 or 12.5:1. As is clears up it goes back to cycling around 14.3:1-15.2:1
Is their anyway to test my CAS?
 
The wideband make a drastic spike as it bucks. Like 16.5:1 or 12.5:1. As is clears up it goes back to cycling around 14.3:1-15.2:1
Is their anyway to test my CAS?

Theres ways to test it but you gotta search for it. I dont know of any specific readings it suppose to be. Im not too much worried about the spike because thats under normal driving, now if it did it at WOT then yea it'll be a problem. But i believe it has something to do with the CAS, Could be a dirty fuel filter..But im leaning towards the CAS.
 
Theres ways to test it but you gotta search for it. I dont know of any specific readings it suppose to be. Im not too much worried about the spike because thats under normal driving, now if it did it at WOT then yea it'll be a problem. But i believe it has something to do with the CAS, Could be a dirty fuel filter..But im leaning towards the CAS.

Wouldnt it cuase problems at WOT is it was the CAS?
 
I was just on a subie forum and adding grounds or replacing with bigger does work. I did it in my KIA and problem went away. I'm gonna replace all tonight.
 
Today I was doing a BLT, only leak was the BISS.

When I was putting everthing back together I decided to clean the pins on the MAF and MAF connector thinking maybe they were getting a bad connection.

While I was doing that I found a slit in the green/yellow wire on the MAF connector. I pulled the slit open and the wire was broke. I striped the insulation back and soldered the wire back together and put heat shrink tubing over it. I searched and it said that the green/yellow wire is park of the intake air temp sensor and Im thinking thats why is got worse the warmer it was outside. Im getting ready to take it around the block to see if the problem is gone ill report back later to let everyone know it it fixed the problem
 
I had a smiliar problem my rpms would fluctuate at. Idle And stall And would fluctuate And buck at any speed except when I had it wot then one day when it was idling And the rpms where fluctuating I unplugged the egr solenoid it ran perfect so I took the egr valve off cleaned it and reset the ecu not a problem since.
 
Ive been having a similiar problem with my 95 gsx it's mostly stock spectre air filter and cat back straight pipe. and a act 2100 clutch. but when i'm driving and go to give it some gas it just doesnt go like it should. i thought it was a brake dragging but it only does it ocasionally. ive changed both of my front caliphers. bled the brakes and such and it still does it. i have no cel. i only have a reg a/f ratio gauge, oil press and boost. and all seem to be normal when it does it. even the bov lets off when i get out of it and get back on. i'm just lost and i've replaced 2 much 2 keep replacing good parts. oh yeah i also changed plugs and wires to ngk iridium plugs and wires. Please help i'm somewhat new to the 4g63's and dont have a clue as to where to go next, thanks in advance and sorry for the long post

jus checked my maf sensor wires and they dont look bad. and one other thing my coil pack was moved from it's stock location to behing the brake fluid resavoir. but none of the wires look bad. i also have changed the fuel filter when i first got it jus for the sake of it. but that was be4 this started happening.
 
Occasionally I've heard of cases where moving the coil location produced weak spark. Possibly the magnetic field needs to be close to the head's metal. Yet I've also heard other cases where even moving it to the firewall has not been a problem. I'm sure it depends on the year, design, etc. Since you changed all this it may be your problem. If you can relocate it to be bolted onto the head this may do better. Even if all you do is temporaily try this just to see if it helps. If you can't, try bolting some heavy wide (must be wide - 1" or wider) wire mesh braid from the coil's bracket to the head to help transfer the higher frequency magnetic field (although this may not work - bolting to the head is best).
Did you also move the power transistor? It's base is a conductor for both current and heat.
 
well the guy i bought it from moved the coilpack he said that they have a tendency to get really hot and go bad in the stock location. but it didnt do this when i first got it. It jus randomly showed up and it doesnt do it all the time. mostly it does great and acts jus like it should but when it does it all i have to do is let off the gas and get back on and it stops. my first guess was the crappy stock bov i have. I was also looking at my tb today and i remembered reading a forum about a biss screw? it looks like there is a screw missing in it. neone have picture of a tb and the biss screw in? also i have a bad gas mileage problem also i only get close to 200 miles a tank.
 
No i've really been wanting to do a BLT but i'm not very familiar with it and i dont have a air compressor. and no i havent done anything to the TB. but the hole i'm talking about is to the left of the biss screw and proabally half the size. theres also not a rubber piece over my biss screw. I drove it tonight and it's gotten at least twice as bad. it looses all power and the exhaust sounds really diffrent. it jus has no pick up. one thing i should have said before also is my valve cover has 2 hairline cracks. and theres a small oil leak somewhere on the timing side of the engine. but all this was there b4 this started happening. I apreciate those links man theyll prob keep me from breaking something else this weekend. i've thought of taking it to a mechanic but i want to learn these cars. i have a deep passion 4 dsm's since i had my 95 gs. sorry 4 the long posts it's jus really nice to talk to someone who knows what theyre talking bout :)
 
Here's a pic of the 2g TB. Perhaps you can say where this hole is your talking about on it or take a pic of yours and point to it.

And here's how to do a BLT (I also show a homemade tester in the 3rd post): http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html.

Also a very easy thing to do is check all your intake air tubing connections for tightness (just use your hand) from the air cleaner all the way to the TB. I had one get slightly loose (but looked ok to the eye) right at the TB and my engine ran like crap.
 

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it's the hole right above where the top right hand bolt hole that bolts the tb to the upper ic pipe i put my finger over it while it was running and couldt feel any air being pulled into it. and yeah i'll try to get that boost leak test done asap. I called a mechinic and asked him do they do boost leak tests, he said you mean compression test? thats why i hate to carry it to a mechanic around here.
 
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