New here hope I can get some info on my car . Just bought her she was running pretty good I gave her a good tune up plugs wire had to replace tps maf sensor egr she just does not want to run good , she start up good but then die check fuel pressure car off 45 psi but then dropped s to 30 after sitting for 10 min won't stay running to find out what the pressure is there any help ty.

 

2.8 v6 ?