Travenport

iTrader: (7)

Hey all,

New member here and was wondering if anyone could help me out.

Been having some recent problems lately with my evo 8 performance. Whenever I accelerate beyond 4-5 thousand RPM's the car starts hesitating and i get a popping sound from what sounds like the exhaust. I dont know for sure whether its a misfire or backfire, but I decided to bite the bullet and take it to the dealer to get it checked out before I caused any major damage. (New to the pensacola area so i dont know of any performance shops yet).

But anyway, there was a list of things they said could be causing the issue. I just wanted to get a second opinion so I can fix the correct problem right off the bat and get around to fixing everything else later.

-First, they said I should be using NGK spark plugs because the Bosch ones dont meet the correct standard.

-There is a slight leak in the coolant line

-Apparently the O2 sensor is malfunctioning as well

would these problems cause a misfire to happen all of the time or is it something more serious?

barneyb

You took it to the dealer, so why isn't it fixed?

The leak could cause the problem. Did they say where it is leaking?

I don't think the brand of plugs is causing the problem. However, they should be plugs intended for this engine.

A bad O2 sensor might be the cause, especially if it is intermittent. Most likely though, it would just keep you from running in closed loop and get bad gas mileage.

Travenport

iTrader: (7)

Thanks for the reply

it wasnt fixed because they didnt have any of the parts in stock.

Do you know of anything else besides what the dealer listed that could cause an issue like this? Im trying to avoid dumping money into something that might not fix the issue, and trying to expand my knowledge-base for anything that might happen in the future.

timmyk12

iTrader: (2)

Had the same problem sort of...it felt like mine was losing power, and i felt a "popping" and hesitation from the engine past 5k. I took it in and had the plugs replaced, they were pretty fouled out. If the plugs are fouled, your car could be running rich. I had to have my car tuned, and it solved the problem

1UpMoto

iTrader: (14)

Throw some ngk plugs in there and Im sure it will go away.

Travenport

iTrader: (7)

thanks for the replies

that sounds just like whats going on timmy. Do you know what the shop did exactly when they tuned your car?

1up, I will try that and see what happens.

barneyb

Usually no parts are required to fix a boost leak.

Travenport

iTrader: (7)

sorry, wrote the wrong thing, there is no boost leak. I meant the coolant, not intercooler

mmmmbst

iTrader: (6)

its your plugs. throw in the NGK BR7ES an gap them at about .028. Evo dosent like Bosch plugs plus youre probably blowing out the spark.

Sim2k

iTrader: (5)

Swap the plugs for NGK's, I had the same problem when I got mine, put NGK's in and it fixed it instantly. I will never use anything else.

Travenport

iTrader: (7)

Thanks for the responses guys. Ill post back up in a couple weeks after I get the plugs replaced (going out of town on a business trip). I really appreciate the help though.

TurboTim06

iTrader: (2)

Start with plugs for sure! Especially if ur running higher boost!

Travenport

iTrader: (7)

Success!

Switched to the NGK plugs and my misfiring is gone! Thanks for all the help everyone. I have one more quick question though.

As I was testing out the new plugs, everything started up fine (maybe a slightly higher idle), but as I was heading back home my idle was significantly lower. It felt like the car was going to die while I was at a stop light. Is this something I should be worried about, or is the computer just getting used to the new plugs?

EDIT: after a couple hours the idle is back to normal. guess the computer was just getting used to the new plugs