Hey all I searched for a similar topic and found one similar to my situation but it wasn't the exact same. I have a 03 ap1 and when I hit vtec it sputters and feels like its fighting to climb higher in the revs. My first though was its the fuel pump or along those lines. it also, for some reason stalls when it hits the 2/3 blocks when its warming up. I've put so much money into my S when it comes to the rear end (Rebuilt it once, second time around put a Spoon sports two way diff, (which ratchets :\ ) and a reinforced diff housing) I dont want to get rid of my S but I'm sick of constantly fixing it. I suspect it was totaled due to the fact every garage asks me if it was, and if it was fixed by the owner because new problems keep popping up all the effing time. Right now other than the ratcheting diff this is the only problem with it seeing as all others were fixed. Sorry for the rant but if ya could throw your two cents in on what it could possibly be that would be awesome. Also it will rev to 9k easy when the clutch is not engaged but like I said it fights its way through vtec when it is. Thanks all.

 

start with the sparkplugs, how many miles on them ? . Pull them out and have a look at them, see if the gap is overly large or past the service limit, check the colour of the plugs - rich or lean, and see if they are oil soaked. Your issue is likely going to be with the ignition of the air-fuel mixture and the plugs will give you some insight into that. Poor spark, running lean, running rich, or oil in the cylinders. After that I'd suspect the coils or injectors, fuel pump would be further down the line IMO.

 

Okay, I'll definitely look into that. The plugs aren't old but they aren't exactly new either. I did have a bad ignition coil which I replaced and have a spare on hand just in case. Replaced the valve cover gasket too because one of the ignition coils was covered in oil. I'm going to check the plugs today and see whats going on. Thanks for the insight.

 

Oil on the coils will definitely cause issues. Perhaps you have additional oil on the other coils?. Did you change all four of the round sparkplug tube gaskets ?

Remember to torque the plugs to 18 foot lbs . If you had one coil go bad , the others could be starting to fail too, hard to diagnose until you get a mis-fire.

 

Just replaced one of the coils. The garage "replaced" the bad one. ....Well they didn't. That helped a lot. Still not 100% though. The plugs are okay but could stand to be replaced. Thankfully there was no oil on any of the other coils/ plugs. Im just going to replace all the coils and plugs next week when I change my oil and see how that goes.

 

A dirty/loose connection on the MAP sensor will cause high RPM sputtering. Some do a whack but I suggest cleaning the connector and using a zip tie.

 

Alright, I'll definitely try that as well. Not going to leave anything to chance.