Cobra engine stutter/hesitation

[brothmc]

So my car is just not running right. It is stuttering slightly and I can feel a vibration/hesitation of the engine under acceleration and there is an odd smell after hard acceleration. The car has full power even at high rpms it just seems labored and running roughly. Dont know if this has anything to do with the recent replacement of the supercharger intercooler but the symptoms started shortly afterwards. I cleaned the MAF and air filter, changed the spark plugs and used a gas treatment/cleaner additive to no avail. Any ideas what this might be? It is not throwing any codes so I am clueless. Thanks for any help!

 

[brothmc]

nobody here ever had trouble with coolant 'disappearing' due to a potentially cracked intercooler then replacing it only to have the car run like crap and smell odd under acceleration??lol somebody?

 

[quikcobra]

Timing? Plugs too hot? If you can feel it sputtering it could be detonating. What new supercharger did you put on?

 

[brothmc]

no new supercharger -just the intercooler for the supercharger started leaking coolant into the engine after it started overheating due to a busted radiator fan. It started drinking sc coolant and bogging down the engine so i replaced the intercooler now this! driving me mad!!

 

[hotcobra03]

cobra

what did you gap your plugs at/ and what type of plug?

how long did you drive it after working on it?

i had a similar problem after changing head.my o2s went bad from the coolant going thru exhaust,but i did get a code

the only other thing that comes to mind is a vaccum hose might have cracked while doing the job

 

[brothmc]

I gapped them at the recommended .052-.056 and continue to drive it daily. It is running just slightly off - im thinking maybe it is a head issue as opposed to the intercooler? ugh!

 

[hotcobra03]

I gapped them at the recommended .052-.056 and continue to drive it daily. It is running just slightly off - im thinking maybe it is a head issue as opposed to the intercooler? ugh!

that way too much of a gap...drop to 35....i use the stock plugs ford sp471 for 1st run cobras...my tag said 42-46 but gap at 35..

 

[brothmc]

unfortunately this problem started before the spark plug change that I hoped would resolve the issue

 

[hotcobra03]

cobra

do you still have the old plugs? what are they gapped at?

i did see fords manual says 52-56 but it could just be a mistake...

i have had this problem before,car would studder under light acceleration,very bad at low speeds...for the time and cost i would change gap to find out for sure,,,i would also do a compression check

was this problem there before working on the blower also

 

[brothmc]

Ruled out spark plugs as the issue as the old plugs were gapped at 52-56 and the problem started before i tried to troubleshoot by changing plugs.gotta be something else...I erased and re-installed the tune also but that didnt work either

 

[hotcobra03]

plugs

Ruled out spark plugs as the issue as the old plugs were gapped at 52-56 and the problem started before i tried to troubleshoot by changing plugs.gotta be something else...I erased and re-installed the tune also but that didnt work either

i had an older boss that gave me 101 on plugs...

here is what he told me and this was confirmed on this site to be very close...

plugs are made to proper gap,than you can make a slight change..

looking at plug you have a post that is flat on top..the arm has to be equal to post..which would make the spark even all around...

look at old plugs at eye level..look and see if the end of the arm and you will see at 52-56 the end is higher than level to post..get it as close as you can by eye than check the gap again 35-40 should be close.

when you gapped your plugs did you use the cheap round metal thing and pry up with it to get to 52-56...that will bend the tiny post and ruin plug,

what type of plugs are you using?

i also didnt believe the gap thing would cause a studder and asked on svtperformance,i was told to lower gap and i learned the hard way

 

[brothmc]

dude it is not the spark plugs but thanks for your help! The problem came after the intercooler change and before the plugs

 

[hotcobra03]

studder

there are many threads on here with problems after working on the blower..

who did the work on blower?
was the lower intake removed?1 loose bolt will cause this problem
were new o-rings used on intercooler? leak here will cause this problem

dont think these problems would send cel

i do believe most of the vacuum and electrical sensors will give you a light

the head could cause this also..of the 3 that went on mine this last time was tiny crack allowing water into cylinder.car didnt blow white smoke till after you turn engine off..car had a studder like your but i did overheat first which made me keep an eye on it

how much did it cost to do this job?

question..when the inter cooler was removed did any of those tiny bolts snap off?

i had 1,and after cooler was off we seen that it was repaired by who ever built them

goodluck not sure why you didnt get more replys back,this site is very helpfull

 

[brothmc]

Just a local shop here in Gainesville replaced the intercooler for about $400 plus the cost of the intercooler (300) and they said they did have to remove the lower intake and there were some damaged hoses in the back of the sc that were replaced as well as the gaskets.

 

[hotcobra03]

studder

Just a local shop here in Gainesville replaced the intercooler for about $400 plus the cost of the intercooler (300) and they said they did have to remove the lower intake and there were some damaged hoses in the back of the sc that were replaced as well as the gaskets.

its hard when your not the one who did the work...

did they offer anything,or are you stuck with it...

i do all my own work and im a dumba$$...i had to after warrenty ran out..

with manual and svt i was able to diagnose my car/strip engine down to crank and reassemble...this car is very easy to work on..

dude all 276,000 miles we did..other than head engine is orig,,

any way you can post some good pics of around blower...maybe something will jump out to others..

if you are stuck with it.you need to go over everthing they did which you will need to remove everthing they touched and comb thru it,

than have you used your handheld to monitor your sensors and compare to values in manual?
your ltft /stft could be off but not enough for cel to trigger...dumb stuff like that
i have my car apart now if you need any pics of something you cant see..

ive taken off my blower many times for pcv blowing and during diagnostic.

its easy the 3rd time around

funny thing...when i had to find out what was wrong on 1st repair..i was hard headed and didnt listen to what was said to do..weeks later and alot of home schooling problem was found...i did learn alot,,but the other guys were right on the money,,,they all said start with a compression test

 

[brothmc]

turned out to be the intercooler water pump not circulating coolant

 

[Blueline]

Thanks for posting what was causing the problem. Glad you got it fixed!