Hey guys I'm new here but I've been reading threads here forever and now I'm stumped completely ok I have a 2001 chevy blazer and ill start from the top I bought this truck over a year ago it currently has 200k plus on it in miles now but I started chaseing a random misfire so I replaced the cam crank tps maf map iat air filter spider fuel pump fuel filter distributer cap rotor coil and 02 sensors I replaced tune up parts with ac delco the distributor is rich porter. But has ac delco parts on it along with plugs and wires also I replaced the egr valve and gutted the cats no emissions where I live also I have cleaned the throttle body now I don't have a random misfire at all as of now knock on wood but I replaced the spider with a bwd at first but it crapped out after 2 months and a can of berrymans on my way to work I figired it was a fuel issue so I took the intake off and ran a fuel pressure test well vice versa but anyway I bought a delphi put it in and she purrrred after looking like I seafoamed it for 20 mins so I drove it and I noticed it had a stumble or rather hesitation around 2k rpm or past 2k but then It picks up and on cruise it kinda has a intermittent jerk or surge I changed plugs and it seemed to help but a few miles later I felt it again. So I started spending money again with luck this has been going on for over 6months I recently gutted the cats and changed the 02 sensors it now stalls at idle while in park with no warning just idleing this happened before I got rid of my cats and after I have no ses the vacuum lines have been replaced under the hood pcv isnt very old neither can someone please help me I'm pulling my hair out

 

I'm having the same issue you are with the bouncing/jerking. Mines inbetween about 2k-3.5k although not really existing around highway speeds.

Replaced a bad engine coolant sensor(car wouldn't get up to temp) and then test drove it ran perfect and didn't hesitate at all. then the issue came back a few drives later.

 

Wow that's a lot of long sentences. Hard to read.

Check fuel pressure and leak down. There is a how to on this site.

 

Thanks for your replies I have a brand new ac delco fuel pump I put in about 6 months ago and spider which is Delphi I've also tested the fuel pressure a few months ago just out of curiosity after I put the spider and fuel pump it was good but my problems started after the first bwd spider took a dump as stated I'm looking at the purge solenoid by the tank although its a crappy guess its the only thing I haven't replaced

 

As mentioned, check fuel pressure and leakdown at the service port and at the fuel filter outlet, then post all 4 numbers: https://blazerforum.com/forum/2nd-ge...eakdown-88305/


The crankshaft position sensor relearn MUST be done. This is not optional, it is part of the job when replacing the sensor. It requires a capable, (high end) scan tool.


Camshaft retard needs to be checked and adjusted if necessary. This is not optional, it is part of the job when replacing the distributor and/or camshaft position sensor. It requires a capable, (high end) scan tool.


These are all basic things that the PCM can not check, and they must be correct before we can get any accurate results diagnosing the problem. Once they are correct, clear all memories in the PCM and perform the General Motors Driving Cycle and post any DTC's that set in memory.