Hiya just reading through this as mine has just started, either 1st or 2nd gear if you rev it over 5000rpm when it normally pops and bangs it feels like it goes in to a limp mode, kills all power and won't accelerate over 5000rpm now until I knock the car off and restart it... did anyone get any look from the dealership before I take mine in??
I agree ^ as above, it's Hyundai's problem don't make it yours.
Limp mode won't let you get anywhere near 5000 rpm, 2500-3000 RPM tops. It's not the limp mode kicking in. It could be any number of things from a faulty pressure sensor regulator to a HPFP regulator going bad.
Needs to be hooked up to the dealers GDS along with checking; Fuel lines, fuel rail, external fuel filter, and fuel pressure sensor and regulator. P0088 is commonly caused by a kinked fuel line, this is usually due to something hitting the line. The only way to see this is to perform a thorough visual inspection.
To many problems connected with the fuel rail pressure being to high, to diagnose without it being looked at directly by a qualified mechanic.