I remember having a starting problem in one car (among too many other problems, which ultimately doomed the car). I did some online research, and found that one common cause was a sensor. I think crank position, but that doesn't matter. What got me was that there were people saying that the sensor in this particular car could act up, and the only way to rule it out for 100% certain was to replace it. I don't know if they were right, but I assume they know more than me (which isn't hard to do). I recall shuddering at the idea--the sensor was something like a 2 or 3 hour job. I multiplied that by the going labor rate (I don't feel I have the ability and I certainly don't have the tools to do it myself). $300 or whatever...which might not fix the problem... 

Of course, a mechanic could start by ruling out things that are easier/faster to check.

One other "joy" on this car was another starting problem that it always had during the time I owned it. If the car sat for more than a couple of days, it would be hard to start, and ran poorly. Once warmed up, it would be back to normal. A cold start the next day would be just fine. This car had belonged to the wife of a mechanic, and he said it was hugely frustrating for him. His wife had the same problem I did, and she'd come to him to complain. But, by that point, she'd driven it enough that the gremlins had gone away.  He'd get in, and the car would behave. (One suspects that he could probably have banished the problem if he got really aggressive. But it probably didn't feel worth it, given that the car ran just fine when driven regularly.) 

The injectors themselves?  Fuel pressure regulator?  My GMC Jimmy was having a problem dying...I had to drive it with two feet to keep it running, no big deal since my VW is a stick anyway so easy to drive with two feet.  But anyway, it was the idle air control valve.  I changed that and it's been fine ever since. 

I used to change spark plugs in our previous Devilles with the 4.9L V8 by lying on my back under the car and reaching up to the back of the engine....

Hey Ken,

I had the same thing go wrong with my 2001 GMC Jimmy but I had zero symptoms.  We went to the lake one night, launched the boat and floated all night,  pulled the boat out of the water next morning and drove home.  Parked the Jimmy and went to bed.  Got up and went out to start...no start.  Checked fuel pressure with gauge and it was way too low.  Priced pumps and labor...ordered new Delphi pump on Amazon for $150 and spent a day dropping tank and replacing.  Wasn't too hard just tedious and had to solder new updated connector on.  But fired right up!  I read online from forums to avoid Autozone and Advance Auto parts fuel pumps because they are crap so went with Delphi who makes the Delco one for GM.

And you have my deepest sympathies. When I was having problems with my '98 Buick 3.1, I got the same list of do this, do that, do the other thing.

I've got the tools and ape-long arms, so was able to work through them. The crank position sensor replacement helped - those things are apparently a weak point of GM's Excellence in Engineering (cough, cough), but what finally did it was something totally different.

You'll get it. There are pressure tests, by the way, before one spends the money. Not even difficult or expensive - they should start there.

Oh, and here's something which might be causing this and you might not have checked it - the anti-theft systems GM used throughout the '90s up to 2005/6 sometimes would not trigger a security display but still not activate the fuel pump every time. That could be part of it.

Robert, I hope this new fuel pressure regulator solves your problem!

Question, is it hard starting all the time, hot or cold?   Or only after it sits a few hours?  (edit: I missed that you noted it's sluggish off the line.  Does power improve as RPM's build?)

My best friend has an early-mid 2000's Chevy truck which had an issue like this.  If it sat more than 10-15 minutes after driving, he'd have to crank & crank (15-20 seconds) before it would start.   After replacing the fuel pump (non-OEM), he would like you, have to turn the key on about 10 seconds before cranking and it would then start.

Bottom line in his case, it was a check valve in the fuel pump, allowing the fuel pressure to bleed off after sitting 10-15 mins.  The replacement aftermarket pump check valve worked better, but not perfect.  So after living with it for 9-10 months, he sprang for an OEM pump and it now starts as it's supposed to every time.

Kevin

If a car was assembled on Monday or Friday it might well be low on fluid leaving the factory. LOL

be wary of even changing fluid in a high mileage unit. Sometimes high mileage transmissions need the grit and varnish to keep from slipping.

From what I've heard, it sounds like it isn't high mileage that's a problem. It's when it's high mileage with fluid that hasn't been properly maintained (e.g., a transmission with high miles that still has its original fluid).

Well new fluids have improved components  in them.  Like Dexron 6 that can be used in an old car but Dexron 3 can't be used in a new car.  I'm sure the fluid itself on the shelf is perfectly usable but I'd personally rather have "new and improved" fluid in my old SUV.