The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support STM Tuned

420A need help RS laggy acceleration, backfiring

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Slow_Rs

Proven Member
50
2
Oct 23, 2020
glasgow, Kentucky
i have a 98’ rs and i have no idea what’s wrong with it, when the car first starts and running it’s fine but does have a little delay with acceleration then when it gets hot it’s fine other from the acceleration, i turn it off then turn it back on and then it will sound cammed and it will backfire from the manifold. i’ve replaced the IAC check plugs and wires, they’re fine, the EGR got taken out and idk if that has to do with the issue at all, any help will be appreciated!
 
Deleting the EGR will not make the car misfire.

When you had the plug wires out, did you notice any oil in the spark plug tubes on the head? Sometimes the VC gasket will leak and let oil down in there causing and interruption in spark, a misfire.
wasn’t any oil on them, i have replaced the vc gasket, iac and the ignition coil and still no luck.
 
timing is fine checked that and also check the injectors and they’re fine as well, pulled the fuel filter today and it was extremely clogged so i have to put that in, it it doesn’t help then i’m lost.
 
what’s the best way to test it?
Not sure, but it's only a $20 part and it would only help, if anything, to replace it. Best way to tell the age is to see if the tip is worn down or if the o-ring is still in one piece. If it's never been replaced then I would go ahead and replace it regardless of how it looks.

A few months back I spent a few hundred dollars on all new engine sensors just to be sure the engine was healthy.
 
Not sure, but it's only a $20 part and it would only help, if anything, to replace it. Best way to tell the age is to see if the tip is worn down or if the o-ring is still in one piece. If it's never been replaced then I would go ahead and replace it regardless of how it looks.

A few months back I spent a few hundred dollars on all new engine sensors just to be sure the engine was healthy.
alright i’ll also look into that, i appreciate the help!
 
Not sure, but it's only a $20 part and it would only help, if anything, to replace it. Best way to tell the age is to see if the tip is worn down or if the o-ring is still in one piece. If it's never been replaced then I would go ahead and replace it regardless of how it looks.

A few months back I spent a few hundred dollars on all new engine sensors just to be sure the engine was healthy.
Not sure, but it's only a $20 part and it would only help, if anything, to replace it. Best way to tell the age is to see if the tip is worn down or if the o-ring is still in one piece. If it's never been replaced then I would go ahead and replace it regardless of how it looks.

A few months back I spent a few hundred dollars on all new engine sensors just to be sure the engine was healthy.
i replaced the CPS and the MAP and it’s still doing the same thing, i am lost.
 
What modifications have you done to the car? Anything that effects air intake or fuel delivery? You could just have a bad air to fuel ratio.
have an aftermarket header and a cold air intake, could o2 bank one sensor one not being plugged up cause the issue?
 
What modifications have you done to the car? Anything that effects air intake or fuel delivery? You could just have a bad air to fuel ratio.
i’ve also noticed when the car starts to act up it’s sounds like it’s trying to suck in as much air as possible
 
could o2 bank one sensor one not being plugged up cause the issue?
You mean you don't have the first O2 sensor plugged in? Yes, this could absolutely be the issue.

It is ok to leave the 2nd O2 sensor unplugged because that only tells the ecu if the catalytic convertor is functioning. But the first O2 sensor determines how lean or rich and the car is running and adds fuel or air accordingly. Like I said, it could be a bad air to fuel ratio.
 
You mean you don't have the first O2 sensor plugged in? Yes, this could absolutely be the issue.

It is ok to leave the 2nd O2 sensor unplugged because that only tells the ecu if the catalytic convertor is functioning. But the first O2 sensor determines how lean or rich and the car is running and adds fuel or air accordingly. Like I said, it could be a bad air to fuel ratio.
makes sense looked at it this morning and the car didn’t even have one LOL, after work i’ll get it all plugged in and everything and see if it solves it.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top