Help with 98 Chevy 5.7 misfire not running right

80

Asked by Feb 03, 2015 at 01:50 PM about the 1998 Chevrolet C/K 1500 Silverado Extended Cab LB

Question type: Maintenance & Repair

Hello. I have a 98 chevy 1500 5.7. The truck doesnt run right at all. Msifres bad under acceleration. Idle ok when misses when reving and accelerating. I did a full tune up including plugs, wires, cap rotor and a new distributor. With key on i have about 60psi fuel pressure but idleing i only had 50psi. I put a complete new fuel pump unit in and changed fuel filter. Same problem. no different fuel pressure. I changed and replaced the spider injector with the new updated system. changed all intake gaskets. That didnt make a difference either. Replaced tps sensor and map sensor. Removed egr valve and it isnt sticking or anything. I cleaned it and used new gasket and put back on. Still same. I know these trucks need 60psi when idling. Cant figure out why i only have 50. I replaced everything in the system. I removed the fuel line where id goes into the spider system and plugged it and have 80psi when i turn the key. then i disconnected the return line by the distributor and plugged it and had 90psi there when idling but engine ran the same. i dont know where to look next. please help
Thank you
Jon

2 Answers

80

also to add, i was getting a p300 misfire and a p122 tps sensor code. thought it had a bad sensor thats why i replaced it. sensor code hasnt come back yet but just did that this morning and still messing around with it. could i have a bad spider injector causing the low fuel pressure?

3 of 3 people found this helpful.
30

What's the battery and alto stir like? If one or the other is bad it may not be getting enough voltage.

1 of 1 people found this helpful.

Your Answer

Add photo

Related Questions

  • Help with 98 Chevy 5.7 misfire not running right 2 answers

    Hello. I have a 98 chevy 1500 5.7. The truck doesnt run right at all. Msifres bad under acceleration. Idle ok when misses when reving and accelerating. I did a full tune up including plugs, wires, cap...

    1998 Chevrolet C/K 1500 Silverado Extended Cab LB

    -

    Maintenance & Repair

  • 98 Chevy Silverado 5.7 4x4 will turn over but will not start 3 answers

    98 Chevy Silverado 5.7 4x4 will turn over but will not start

    1998 Chevrolet C/K 1500 Silverado Extended Cab Stepside SB 4WD

    -

    Maintenance & Repair

  • 1996 Chevy 350/5.7 (with '97 Engine) Low Pressure Switch is not receiving power! 1 answer

    I have replaced my Compressor (bought a new Delphi), orifice tube, drier, AC Control Unit, and Ac Relay. Flushed out the system and added Freon. The system pressure is adequate. I've had to put a me...

    1996 Chevrolet C/K 1500 WT Standard Cab SB

    -

    Maintenance & Repair

  • My 99 Chevy 5.7 turns over then dies right away. 7 answers

    My 99 will turn over but then dies right away. The fuel pump will cycle so I know it's working. Wear should I start problem checking

    1999 Chevrolet C/K 1500

    -

    Maintenance & Repair

  • 98 chevy truck 4 answers

    I have a 98 chevy z71 that will not start unless u pour gas down into the intake have changed the fuel pump plugs wires distributor cap rotor button coil and throttle positioning sensor when u get...

    1998 Chevrolet C/K 1500 Silverado Standard Cab SB 4WD

    -

    Maintenance & Repair

Search Chevrolet C/K 1500 Questions

Chevrolet C/K 1500 Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 3,420
#2 John Saffrahn
John Saffrahn
Reputation 2,530
#3 Rowefast
Rowefast
Reputation 2,100
View All

Related Models For Sale

Used Chevrolet Silverado 1500
1,837 Great Deals out of 182,461 listings starting at $1,595
Used GMC Sierra 1500
763 Great Deals out of 69,762 listings starting at $1,800
Used Ford F-150
2,067 Great Deals out of 208,216 listings starting at $290
Used Chevrolet C/K 2500
217 listings starting at $8,200
Used Dodge Ram 1500
426 Great Deals out of 10,962 listings starting at $1,000
Used Chevrolet Tahoe
587 Great Deals out of 32,526 listings starting at $1,500
Used Toyota Tacoma
502 Great Deals out of 42,079 listings starting at $1,995
Used Chevrolet Camaro
246 Great Deals out of 31,906 listings starting at $1,000
Used Chevrolet S-10
5 Great Deals out of 1,346 listings starting at $1,500
Used Chevrolet C/K 3500
237 listings starting at $4,797
Used Chevrolet Silverado 2500
5 Great Deals out of 254 listings starting at $4,200

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.