Very hard to start after reaching normal temperature

fuel pressure must be 60-66 psi key on only. check engine coolant sensor for ohms as well. should be 177 ohms at 212 or engine hot. and 3520 at 68 degrees.

All sensors have been replace.

see fuel pressure spec yours are way low.

Fuel at 60 psi and hold pressure for hrs before going to zero psi. Two different garages tested with best scanner all test pass A1.

Spec are between 50 to 60 psi.

wherever you got your spec is wrong ours is 60-66 psi. this system was used from 1997 at least 2010 and spec has never changed. 60 should be enough to start if getting hot and not then I t may be the pump is bad or fuel filter may be partially plugged or return line .

New fuel filter. also, like I said the mechanics are going crazy with my vehicle. I have a 2006 Buick Terraza after $2,000.00. Repairs still no heat what can expect we are not in the 1970 or 1980 when they were still building cars?

if not starting hot may be pump going bad and pressure should be checked then or the return line is partially blocked if you can spray choke cleaner into manifold and it starts then it is a fuel problem. also, on these check distributor for play in rotor there should be none if there is the gear is bad on distributor which is a common problem and distributor needs replacing.for no heat for Buick pull fuses in picture the temperature actuator may be need to reset or not working. pulling fuse for sixty seconds with key on resets actuators and you may get heat. if auto temperature it needs to be scanned with a scanner.

I did replace the 2 o2 sensors it improve but not what it should be like I said this was the last 2 parts to be replace

with out scanning for codes you are just replacing maybe good parts. do as I have said in past replies step by step

I got obd2 scanner and was scan by 2 garages no codes even history and all reading are in spec

Hey Tonton4me12,

This sounds like it could be a fuel pressure regulator or a fuel injector that is leaking into the intake manifold which will cause the hard starting. Here is a guide that can show you more

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

Please let us know happens so it will help others.

Best, Ken

There was only one thing to do was to open the top of the motor reinstall gas line and pressurize system the regulator was not leaking nothing wrong with it but gas was leaking at the bottom of the spider block all 6 injectors were leaking there bought a new system now I only have to see tomorrow how it will start after reaching normal temperature and turn off and wait 30 mins and try to start again

O good find!.. that will definitely cause the problem, please get back to us when you get it back together

Best, Ken

It's all back together I'm getting old I'm 60 and stop doing mechanic long time ago but it was simple only 3 hrs for a old man and no air tools it starts ever time like it should and not even plug in for winter 20 /30 / 1 hr after stopping the motor and start first turn over this problem is fix but still using gas like a locomotive lol I don't know how hard is a 4x4 it's my first one I ever bought any one know what could be the amount of kms per a thank I can do 200 kms in city

4X4 are known gas guzzlers if you are getting 12 mph in city feel good