Craq

When running errands, about the third or fourth stop/start, it will crank for three-four-five-six seconds before firing. If I don't turn it off, wait three or four seconds then restart it (always starts normally afterwards) it wont run well. Never happens cold. Is this the fuel pump/pressure regulator issue?

2006 CTTS w/149K miles.

Vivid7

sounds like the fuel pump

jtakhtalian

It could also be emission related. An evap purge valve on its way out could cause that intermittent issue. Especially if it happens right after a fill up. Ever experienced that?

Craq

Does not appear to be fill up related.

Adam5oh

Cranks for a long time then runs like crap? But if it starts normally it runs fine?

I traced a similar issue to a crank position sensor in my 2008.

RSbob

Probably should pull the codes or have it done.

Rossi

Your high pressure fuel pump is on the way out.

Craq

Most responses say fuel pump(s). Some say high pressure fuel pump. From what I've read, the only fuel pumps are in the tank, drivers side and passenger side, accessed from the under the back seats. Can anyone explain how this fuel system works? Does one act as primary and one as a back up? Do I need to replace both?

GDA

^ Yup - could easily be the purge valve going / gone bad. I have gone through 2 of them on my 05 Turbo in the past 10 years and both times it became long cranking when hot before it started becoming hard to start after a fill up at the gas station which is the dead giveaway for purge valve.

J'sWorld

Yes your model year only has two standard fuel pumps. If you are going to replace one then yes, do both, the filter, and the regulator. I could explain how it works but it takes a while. The in tank system is complicated. Replacing them not so much.

You can run a test for the pumps but I agree with the others that it is probably the evap purge valve. You should get a code for it.

deilenberger

There was no HPFP on an '06..

jtakhtalian

The purge valve doesn't always throw a code. I went through replacing fuel pumps and filters before realizing that the issue in my car was the Purge valve. Quick replacement.

DWPC

Purge valve & hose is a relatively inexpensive fix (for a 955) vs the expense of a fuel pump replacement. Mine showed a purge valve code via a $20 generic ODB reader I bought for my GM truck. If you don't have a reader or indie who'll check it for you, most parts stores like O'Reilly's will read it for you.

Craq

No codes, checked it today.

Craq

Update: Changed the purge valve yesterday...didn't fix it. I'll try the crank position sensor next I guess.