Got 2001 blazer.

The car doesn't start as smooth as it used to. I'd put the key in ignition and when turning it on it would always start fast and smooth. I am just not sure what to look into that might cause this problem.

plugs, wires, dist cap and rotor are all new(OEM)
fuel filter 4k miles old
air filter very clean
pcv valve new
fuel pump psi readings good
no check engine light
Ive had the starter alternator and the battery checked at o reillys but they said theyre all good
I've also ran fuel injector cleaners a few times, no change.
Also, when the car starts it runs perfectly, no idling problems no unusual changes in rpm etc


I am going to clean the throttle body opening and the MAF sensor in a bit and see if that helps. If it doesn't tho, what should I look into? Would the O2 sensors cause this without tripping the engine light?

 

fuel pump psi readings good (from where?) how did you test ?

 

it was tested few months ago by a mechanic who was doing daignostics on my evap system(I had a leak on the O ring near the pump) and he said he hooked up a machine early in the morning and he said no problem with the fuel pump.

 

Testing the EVAP system has nothing to do with fuel pressure and leakdown, so he would have no reason to check it. The only way to know for sure, is check pressure and leakdown yourself Most shops don't take the time to check fuel pressure and leakdown at the service port, and at the fuel filter outlet. Without checking both, you don't have enough data to make an accurate diagnosis.

 

He didnt check it due to evap problems, I just had him do that extra since I had the problem back then as well but I haven't had done all the tune ups so I didn't make this post at that time. He didn't tell me which way he checked nor did I ask but I remember he said it was reading 60 psi.

Is the fuel pump the only thing that can cause this?

 

Have you checked the battery connections? Both at the battery and the starter and ground? I like to eliminate the easiest culprits first.

 

60psi is good, but does it leak down.It can pump 100psi it means nothing if it leaks down during a test the FPR could be bad. You need a test from the fuel rail and the filter port.

Capt helped me a couple yrs ago same type thing (He Knows)

 

I cleaned the throttle body and the MAF sensor. MAF wasnt black or anything but the throttle body was kinda bad... It turns on smoothly now.
Just for curiosity tho is there a DIY post write up for the fuel outlet test? I found an article about the test that uses the port near the distributor cap but nothing else

 

https://blazerforum.com/forum/2nd-ge...00miles-76532/

 

https://blazerforum.com/forum/2nd-ge...eakdown-88305/