Hey guys, good afternoon. Newer member here and 87 Grand National owner since April of 2015. Bought the car with just over 30,000 miles. It was a near stock GN with the exception of an exhaust and an older Hypertech chip. It ran like a raped ape at WOT on the old chip but at idle and warmer temps (above 80*) it would stutter at lower RPMs especially slowing down to a stop. Fast forward to this spring, I upgrade the chip to a close to stock, mild TurboTweak chip. It really helped out the drivability throughout the rev range except now at WOT it would stutter which I chalked up to the 16-17 lb boost limiter. Odometer currently reads 36,340.
Now we get to the issue. One October drive while on a WOT rip I got the stutter up top followed by an immediate loss of boost and rough running engine. I limped the car home and got it into my local Buick dealership. I know, I know what the hell does a modern Buick dealership know about these cars. Long story short I know one of the managers who has had a couple of these and they have a tech who has 30 years there and has worked on these cars. Plug 3 was fouled out, new plugs and wires did not help. Compression test showed 5 cylinders at 90psi. Cylinder 3 had 0. So we buttoned it up and this is where I'm at.
I am by no means a mechanically inclined person who can diagnose this any further myself. I asked if they bore-scoped the cylinder which they did not as they do not have a scope. I thought that would be the next logical route without pulling the head off.
Just wondering if any of you more veteran GN guys had any thought as to what may have happened or what to look for. I live near Detroit at the Michigan/Ohio border and have a few places in mind one being Full Throttle Speed in Fraser, MI. If anyone can point me in the direction of a recommended engine specialist in the midwest I would appreciate it. Thanks for the help guys, I'm hoping to get her back up and running strong this spring! Here is a pic just for the hell of it.
Now we get to the issue. One October drive while on a WOT rip I got the stutter up top followed by an immediate loss of boost and rough running engine. I limped the car home and got it into my local Buick dealership. I know, I know what the hell does a modern Buick dealership know about these cars. Long story short I know one of the managers who has had a couple of these and they have a tech who has 30 years there and has worked on these cars. Plug 3 was fouled out, new plugs and wires did not help. Compression test showed 5 cylinders at 90psi. Cylinder 3 had 0. So we buttoned it up and this is where I'm at.
I am by no means a mechanically inclined person who can diagnose this any further myself. I asked if they bore-scoped the cylinder which they did not as they do not have a scope. I thought that would be the next logical route without pulling the head off.
Just wondering if any of you more veteran GN guys had any thought as to what may have happened or what to look for. I live near Detroit at the Michigan/Ohio border and have a few places in mind one being Full Throttle Speed in Fraser, MI. If anyone can point me in the direction of a recommended engine specialist in the midwest I would appreciate it. Thanks for the help guys, I'm hoping to get her back up and running strong this spring! Here is a pic just for the hell of it.
