sclemmons

Hello Everyone,

I have developed a throttle hesitation in my 2006 997 C4S. This car has been trouble free for 12 years and is a blast to drive. I drove it all day and hesitation never cleared up. Several stops and starts but no relief. Took it on the highway to "blow it out" after weeks at home. Started well and drove and screamed above 5000RPM with the X51 Powerkit with PSE. I have never felt the choppy drive at low level traffic speed. Is this a fuel filter? Plugs? Injectors? It has to be something easy to fix unless it is something computer related.

LMK.

Many thanks,

sc

sandwedge

I had some similar issues on my GTS. Turned out to be the HPFP (high pressure fuel pump). There's another current thread on this if that's what it turns out to be. Mine was replaced at no cost as a recall item. Someone else had to pay for it so I don't know what the deal is. But it could be a number of other issues. How many miles on your car?

sclemmons

About 46,000 miles.

Petza914

Probably plugs and or coil packs. Have they ever been changed?

You have a 997.1 so no high pressure fuel pump like in the 997.2 DFI cars.

TheBruce

Can you define the hesitation a bit more. Like step on the gas and nothing happens, or step on the gas it accelerates then bogs down, or step on the gas and it bucks a bit?

sandwedge

You're right of course but it still has a fuel pump and like I said the symptoms he's describing are similar to what I experienced with my fuel pump failure. Just guessing that you could have similar issues with a non high pressure pump.

Ptech1

This. Keep it simple. Probably aged out and tired ignition coils. And change your spark plugs at the same time. Worst case scenario, you're doing maintenance that should have been done already, while possibly resolving your issue with a common fix before going off the deep end of "forum fixes".
And yes, this car has a fuel pump, but the requirements for DFI and non-DFI systems are completely different. The pumps in 997.1s don't tend to stumble, they typically just fail at which point the car doesn't run, or stalls after running for a short period. With a HP pump issue, the 997.2 system is still being fed by the low pressure pump (normal fuel pump), but just isn't creating the level of pressure required for normal operation, hence the hesitation.

Bruce In Philly

2009 C2S 155K miles

Hesitation is an odd one...... I am not sure about coils as they throw a dash light especially if you can feel their failure. HPFP: not in a 997.1. Most likely, you are describing a dirty throttle body. Easy to redress. For some reason these cars are sensitive to this and that includes all models.... my 2000 Boxster S had the issue too. Read some more here:

https://rennlist.com/forums/997-foru...ttle-body.html

Peace
Bruce in Philly