95 Z-28 hard starting, but runs okay

afternoon folks !

1995 Camaro Z-28, 350V-8 /auto tranny, 144k miles, 20k miles on plugs/wires, 5k on air filter/oil change. running "mid-grade" gas. bought the car at 95k miles - no problems. weather around here is now hovering in the 70s-80s.

up until a week ago, i would simply turn the key and she would start up almost immediately. it was rare i had to use the gas.

now, about 300 miles later, as i turn the key, the engine cranks and cranks an cranks. as is normal reaction, i pump the throttle. it takes probably 30+ seconds of cranking before i get any sort of response (i.e. engine wants to finally fire up).

oddly, when there is a glimmer that the engine wants to start, i lay off on the gas and let go of the key. the engine fires/turns "slowly" (ie - coughing), as if it's firing on 5 or 6 cylinders. and as if by magic, the engine roars up to normal idling as it did all along.

once the engine has been running for a couple of minutes, i put her in gear and move on down the street. at a stop sign, she runs a bit rough, as if missing a cylinder, but once moving, say normal cruising at 35 on local roads, or 70 on highway, she runs "normal".

once warmed up, starting the car isnt instantaneous, but not a real issue ... the 'hard starting' is mostly after sitting overnight.

although i havent started troubleshooting yet, i plan to:

  • check all plugs/wires (ohms) and check wires to sensors for proper connection. check relays
  • change fuel filter and clean air filter.
  • check fuel pressure.
  • check sensors for proper reading.

i'm thinking along the lines of a fuel-related problem, but i could be off on that. the only other obvious issue would be ignition related: coil, wires, or distributor cap/rotor (not sure if the rotor/cap has ever been changed).

is there anything i'm missing? anything special i should concentrate my efforts on? from the description of the problem, is it fairly obvious where the problem lies?

thanks for any feedback you may have! michael

Reply to
LinuxTester
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Have the fuel pressure checked... I'll bet it is a bad fuel pump as a bad pump will "bleed" down over night and have some problems maintaining fuel pressure when it is hot. Same issues with my Mustang some time back.

Reply to
edsinmt

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