HELP: S14 with SR20det blacktop issue

[jdm_eg6]

So recently i started having an issue with the S14. After the car drives around for a bit it starts to hesitate under full boost at 5000rpm, as i drive it begins to hesitate at lower RPM's down to 3000rpm.

At this point the car seems to missfire and wont go past 3000rpm, just like it would not go past 5,000 and so on.

I noticed if i just shut off the engine and turn it back on the problem is fixed untill i drive it for another 15min.

Any ideas??!

in addition: when if i dont boost (remain a low or no boost) and accelerate there is no hesitation or missfire.

[Tram Common]

How much boost are you running? Stock injectors? Have you checked for vaccuum leaks?

First thing I'd do is pull the spark plugs and inspect them, check the gaping and smell them for unburnt fuel. Also look to see if they're all black or not.

First impression to me is you need new plugs. My $0.02 would be to start there.

[peterparker]

maf..??

[DonJuan]

depending on how its misfiring could be vacuum leak or MAF. REALLY bad plugs are a possibility.

[peterparker]

plugs could just be gapped wrong, or maybe like in my buddies old sil he had a cavalier spark plug some other random shit none of them matched. go out and get some decent brand new spark plugs

then check maf

are you runing a cone filter at all??

[jdm_eg6]

This is for my friends car:

And he is running a HKS mushroom filter, this all started happening after we installed a manual boost controller. It has since been removed and still does this.

He bought a new fuel filter, plugs, and i am going to see how she is now.

[sr20s14zenki]

Ouch, how high did you put the boost with the MBC? Are you sure all the boost signal lines you played with are back to normal? Could just be a coincidence, try getting some electrical cotact cleaner and cleaning the elements on the maf. Take the maf right out of the housing, with the two screws that hold it on there. Clean the elements, DONT touch them with anything. Then give er a shot. If you DID up the boost, you MAY have pushed a pipe out of the coupler, and its just kinda hanging in there. Ive had that, where it idles fine, and i have a hesitation, only to find out it was just a bad coupler or a pipe almost blown out.

[peterparker]

Originally posted by sr20s14zenki
Ouch, how high did you put the boost with the MBC? Are you sure all the boost signal lines you played with are back to normal? Could just be a coincidence, try getting some electrical cotact cleaner and cleaning the elements on the maf. Take the maf right out of the housing, with the two screws that hold it on there. Clean the elements, DONT touch them with anything. Then give er a shot. If you DID up the boost, you MAY have pushed a pipe out of the coupler, and its just kinda hanging in there. Ive had that, where it idles fine, and i have a hesitation, only to find out it was just a bad coupler or a pipe almost blown out.

good call

[jdm_eg6]

UPDATE FOR ALL: there was sediment in the fuel tank causing a mad block up of his fuel intake hose (and filter), flushed the tank and bought a new screen. Car runs fine now.