L98 TPI, been running great, ran great to work, then went to start it and started chugging and when I pushed on the gas it would hesitate and even backfired a couple of times. Idle is rough and low, and engine sputters in middle rpm ranges and then can rev up after that. I have done some work over the last year, nothing recent, including good tune up, cleaned IAC and checked TPS, fuel filter, fuel pump, so I feel like the basics are covered. No plug wires seem unlugged and no vaccum hoses off. Any ideas appreciated.

 

maybe clogged fuel rail/fuel line

 

#1 thing, fouled spark plug.... What kind of plugs are you running ? if not...

Ohm all injectors while the engine is Ice cold. This means in the A.M. before you start the car. Say your average reading is 15.9 Ohms. All others should be within a couple of clicks of each other either way. This means 15.7 to 16.2 is acceptable. Poor running conditions created from an injector problem would usually end up with an injector/s with a closer to shorted reading such as 5.5 .
Specs on a average 3rd gen TPI car are like 15.8 to 16.6 . The reading will vary somewhere in the area depending on outside temp. If 7 are 16.6 and one is 15.8 suspect a problem because if it's not it will be. Just because it's in specs doesn't mean jack.

Readings should always be withen a few clicks of each other.

 

Any SES codes?

 

90Formula-X-F, I am running Bosh platinum tips, how do you check the injectors? Post the procedure and I will try that. Engine light has not come on, but I will check for any stored codes and post them.

 

Get rid of those plugs and run some AC-Delcos. R45TS I believe is the correct plug # for a stock sbc.

For injectors, unplug the harness from the injector and then put an ohmmeter across the two terminals of the fuel injector.

After you check that stuff, check your fuel pressure. I kind of had the same problem recently and discovered one of my intake valve rocker arms was off the pushrod Not sure how it happened, must've left one too loose when I put the motor together a couple of days before.

Other thing would be to check timing. Also check your plug wires. Make sure none are burned through on headers.

 

there are no SES codes

The injectors read:
18.2 17.3 21.7 13.3 14.2 12.8 15.7 20.7

Could they be that messed up? Would it matter if I did it in the afternoon instead of morning? If I got them cleaned and flow matched would that fix it or do I need new injectors?