1G Stumbling (jerking) at low throttle...random misfire

[93TSI_DSM]

Ok ill start by saying my car is a 93 Eagle Talon Tsi yes it is a DSM and yes random misfiring is a common problem. Well to get things started my car has a random misfire you can hear it when it idles. I have changed the spark plugs, wires, fuel filter, and have checked the gapping they are roughly at .029-.031 i normally drive to Owens everyday back and forth and dont have a problem but recently i have had the car stumble or start jerking at like <10% throttle its a PITA to drive when it does this i can either get the problem to go away by letting off the throttle and trying to give it gas again sometimes this works but not alot or i can just floor it until it stops misfiring and turns back into a DSM and not a lawnmower. Can anyone help me fix this please its my DD and its getting to be annoying. Thank you guys. Also I have had the ignition coil taken out and checked at autozone which got the "ok..its good" so idk if that could be it or something else i have 550cc injectors that i thought might change it if it was a fuel delivery problem no CEL has ever came on and the bulb works fine it clearly comes on when you turn the key over to start it. OBD1 POS DSM....sigh

 

[Artago]

I have a similar problem I've been chasing for a while now. No luck though.

Have you tried a fuel filter change? I just bought one but haven't installed it yet.

Tom

 

[93TSI_DSM]

I have replaced the fuel filter 2K miles before the spark plugs and wires again this happens randomly somedays it runs fine other days it runs like a lawnmower

 

[Chicken Patty]

Could your TPS Voltage be the culprit? it might be off.

 

[93TSI_DSM]

what would be a way of checking that and what would be the volt be at or i should say should be at?

 

[Jrock11]

How about the tuning it could just be the good old air fuel ratio. Maybe you are running to lean or too rich. What kind of mods do you have?

 

[93TSI_DSM]

Mods...
ACT 2100 clutch kit
Fidanza 8.5lb flywheel
2g MAF w/ K&N filter
2.5in full exhaust
mbc 12psi
rfl bov
2.5inO2 dump
and thats all i can think of atm

 

[Jrock11]

Hmm did it start doing misfiring after putting on any of those mods? If so that could greatly narrow it down

 

[Chicken Patty]

what would be a way of checking that and what would be the volt be at or i should say should be at?

You might find what you need here.

2g TPS adjustment? - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

 

[93TSI_DSM]

no it did this before about 1500miles ago i changed the plugs/wires/fuel filter and the problem went away after i changed the wires but it has recently came back i checked the plugs today and one of the plugs had some carbon build up? and was sorta melted back other then that the other 3 where greyish white

i am going to tap on the injectors tomorrow with a screwdriver and see if that does anything then pull them one by one...

 

[Chicken Patty]

no it did this before about 1500miles ago i changed the plugs/wires/fuel filter and the problem went away after i changed the wires but it has recently came back i checked the plugs today and one of the plugs had some carbon build up? and was sorta melted back other then that the other 3 where greyish white

i am going to tap on the injectors tomorrow with a screwdriver and see if that does anything then pull them one by one...

What plugs and wires did you put in place when you replaced them? Just trying to use process of elimination to our favor here .

 

[my dreamt dsm]

I really had a similar problem. I've changed the plugs except wire. I just happen to have seafoam in the garage. I used it and the problem went away. Weird but that's how I fixed mines!

 

[93TSI_DSM]

NGK BPR7ES Plugs and Borsh Wires

I also used fuel system cleaner and i ALWAYS run 93 octane from sunoco idk is going on

 

[Chicken Patty]

NGK BPR7ES Plugs and Borsh Wires

I also used fuel system cleaner and i ALWAYS run 93 octane from sunoco idk is going on

The plugs are def right, and the gap should not have much to do at the RPM's and throttle % you are having the issue at, I would understand WOT, but not the way you described it.

The only thing I can think of is the wires, maybe try some thicker aftermarket ones that are known to be good, or maybe a new set from auto zone. Even if cheap, new is new and they will work good at least for a bit. Swapping wires from another DSM who has no issues would be great so you can rule that out for sure.

 

[93TSI_DSM]

i mean they are lifetime warrenty from autozone but they only have like 1500miles on them how can they be bad already? ill see if my buddies plugs change anything. If not ill post back

Changed the wires again...no change this is not a spark issue im sure of its got to be something else

 

[Chicken Patty]

i mean they are lifetime warrenty from autozone but they only have like 1500miles on them how can they be bad already? ill see if my buddies plugs change anything. If not ill post back

Changed the wires again...no change this is not a spark issue im sure of its got to be something else

yeah, it's gotta be a sensor or something. Did you see the link on adjusting TPS, maybe you might want to look into that, make sure it'd dialed in right?

 

[lilreg08]

no ill look into the TPS tomorrow when its light out i hope its not the Cam angle sensor on the head that would run me like $200 its just a headache i wish someone would just come help me diagnose this problem

im not having the same problem as that guy and i drive a 1g i am going to pull the injectors tomorrow and see whats up if its them i got 550s and then ill see if its the sensor it could be the TPS CAS MAF ECU Injecotr Coil Fuel pump and one of these things that i dont have the money for i just want to know what it is so i can pay what i have to pay for and get it done

 

[VETTE_50_TH]

Bosch wires are junk. Get NGK, MSD Taylors or similar.

A bad cam sensor should make the car undriveable. Usually low rpm or light throttle problems are ignition related when nothing has been changed. I would change the wires and if that doesnt help try a different coil pack

 

[ifeelubu]

you have 550cc injectors but what fuel pump are you running ? and do you have an aftermarket afpr if not that can be your problem. you need to compensate for your injectors. and you need some type of fuel management like safc or dsmlink.

 

[VETTE_50_TH]

His profile says he has an SAFC but not hooked up yet. Well if it is hooked up now and youre trying to use it, that could very well be the problem. Good find ifeelubu.

 

[93TSI_DSM]

No the 550 are not installed i do not own the SAFC2 anymore i have no major mods besides the 2G MAF clutch kit and flywheel

 

[13b Bro]

How are you compensating for the 2G MAF?

 

[93TSI_DSM]

Im not compensating for the 2g MAF but the car has had that forever and this problem is new as in just out of the blue starts happening

 

[13b Bro]

2G MAF will make you run lean if not compensated for. Do a compression test.

 

[1gdsmftw]

blt it and check the intake gasket...when it blows it causes a stuttering under load and idle...had a similar issue to yours and i changed my intake gasket after a blt because i heard air escaping from it