Supercharged car misses when you give it throttle

[muztangman93]

Had my car tuned about a month ago ran perfect. Then about 5k rpm I started noticing a small miss hardly noticeable. It has progressively gotten bad. Once it went into limp mode but no engine codes. Then worse and worse to the point where if you baby the car it might not miss if you give it much throttle at all it starts stumbling. I get it back to the dyno and they said everything on the tune looked great and it had to be something spark related. I put some coils on it still there pull the plugs and clean them still there. My friend is a mechanic We take it for a ride while hooked up to his reader and with the car missing horribly it showed no miss fires. He said he has never seen any newer cars have a miss and not show a cylinder that is missing or someidea of whats going on with it. He said it felt like the whole motor was shutting down and not a cylinder. What can I look for to get it running good I realy want to enjoy this thing and not just stare at it. I have a bbk throttle body on it and tried putting stock one back on and ran same way as well. Was told fuel pressure was good any help please.

 

[stkjock]

What plugs and where are they gapped?

 

[muztangman93]

They are the hto cant remember gap with the previous blower they were great for a year with this blower it was all good but getting really bad.

 

[stkjock]

How many miles on them and are you running more boost now then before? If u upped the boost did u re-gap?

 

[muztangman93]

didnt regap running 4lbs more boost but was running great and started small then getting bad. probably about 8k miles on them. Wouldnt a code be thrown for a misfire or show on the scan tool that the cylinder is misfireing.

 

[SS KILLR]

Have you looked At the ground straps on the plugs?

 

[muztangman93]

What is a ground strap

 

[SS KILLR]

Not my plug btw. For illustration only. Lol
#2 is the ground strap

 

[muztangman93]

All the plugs looked ok to me but its hard to tell by looking if they are firing or not. At idle seems fine

 

[SS KILLR]

If there not gapped correctly it should seem fine it idle. You could be blowing out the spark. It's when the car starts to boost this becomes a major issue.

 

[muztangman93]

Dont have to pull any boost for it to mis out. Ran fine for a month. Wouldnt a code show up or the scan tool pick up on the misfire while driving the car.

 

[irishpwr46]

id say pull the plugs and re gap accordingly

 

[muztangman93]

I dont have the tool to gap them. If its the plugs Id rather buy some brisk plugs.

 

[irishpwr46]

even if you buy new plugs, you will still have to gap them

 

[SS KILLR]

Buy NGK's I'd say IMO, but that's just me.

 

[SS KILLR]

Contact evolution performance on here and he will you some and gap them for you. Very cool guy.

 

[NUTCASE]

when you pulled the plugs was there a lot of black residue on them? also was there any residue on the spark plug shank?


if no for both try just changing the plugs. sometimes in higher power combinations they can break internally.

and if I can ask why the hell did you pay for a procharger and a tune, but you are only running 4psi? sounds like a waste to me. unless plan on running 8 psi at absolute minimum I wouldn't even bother with the work and money of a SC kit IMO

 

[irishpwr46]

when you pulled the plugs was there a lot of black residue on them? also was there any residue on the spark plug shank?


if no for both try just changing the plugs. sometimes in higher power combinations they can break internally.

and if I can ask why the hell did you pay for a procharger and a tune, but you are only running 4psi? sounds like a waste to me. unless plan on running 8 psi at absolute minimum I wouldn't even bother with the work and money of a SC kit IMO

he said hes running 4 lbs more boost

 

[NUTCASE]

my bad

 

[skwerl]

You can buy a spark plug gapping tool at any auto parts store, often they are in a cup or tray next to the register. Or even try a lawnmower shop. If you pay more than $2 it's too much. I have 3-4 old ones rattling around in the top drawer of my toolbox.