I had an issue a few months ago with bad stuttering under heavy engine load. I fixed that by replacing my stock ignition wires that were arcing. It seems that since then, I've been experiencing the same stuttering, but this time it's only at high RPM when I really have my foot down.

I recently changed my Crank pulley, and I'm worried I did something to the belt alignment causing to it to slip.

Any help is appreciated. Thanks!

 

i doubt its the belt slipping, but how many holes do you have and do you smell it warming up? any diffrence in boost?

my gut is saying its still ignition problems.... are contacts clean and use some dielectric grease on boots to keep water out.

 

Slipping belt under load/high rpms will not stutter/miss/misfire/knock...just lower boost in most cases.....
Ever look at your plugs? Coil still original? Maybe when it gets hot, it stats to my have failures...typical of a failing coil.

 

I agree with Zippy check the coil the #3 terminal is probably corroded. And change the plugs.

 

I replaced plugs with NGK iridiums about 10k miles ago, as well as the coil pack with a second hand MSD pack.

I'm going to order an OBD2 reader and get a bluetooth scanner app for my phone to check the boost.

 

Could this be a problem with the battery? I still have the original and it has 110k miles on it

 

Could be a fuel problem. Under heavy exceleration a weak injector or fuel pump may not be able to keep up with the demand. If you get the Scan Gauge II it will do both (read codes and show boost while driving)

 

Weak fuel pump would get you a lean code...maybe loss of peak power...
IMO, I think you got a bad coil....or a valve issue.

 

My first thought was the coil but OP said they changed it already. Thinking a partially plugged injector(s) could cause a miss at higher rpm because of the fuel demands.

 

I'm going to put some injector cleaner in tomorrow and see what happens even though I use seafoam on a semi regular basis.

I'm maybe thinking I should put my stock coil pack on for a day and see what happpens because I never had this issue with it.

All these issues started after I replaced the crank pulley with a fluid pulley just to be clear.

 

When I had these issues go w/ hard starts, I went thru plugs , coils, vac hoses/tubes, pressure regulator, fuel filter...Nothing, no change....left the messiest for last: fuel pump..... It turned out to be a torn in-tank hose that runs fuel from pump to filter. 22psi was less than half of 55 & NO CODES. Fixed that by replacing w/ some 30R10 submersible fuel hose. All issues cured instantly.
Mine was probably the lone documented case in the boards under X-Files at the time. Then came a call last week from a friend having similar symptoms w/ HARD START.... Told him my journey w/c he cut short. & Bang!!!! Same case of brittled hose.
Yours may be among the many possibilities of ignition, BPV, vac & fuel delivery. Shouldn't be too difficult to pin down. You just gotta go thru each a step, a time.
Good hunting!

 

So I found the problem today. It was a spark plug that was damaged from when my crank pulley failed and the engine overheated. It actually melted the threads on the plug and it was scary trying to remove because I thought I had screwed up my threads.

You can see the buildup go to the top of the plug almost. The old leads I was using were all burnt up which Is one reason why I replaced them, but I never thought to replace the plug...doh!

 

Glad you solved it.

 

Thanks for the help everyone