Help with 98 Chevy 5.7 misfire not running right

60

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

60

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?

2 out of 2 people think this is helpful.
20

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

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

  • 97 chevy 5.7 cam crank relearn 45 answers

    When replacing the distributor on the 5.7 Chevy Vortec enginen, the instruction that came with the Distributor said that a code P1345 would be set, and that a Cam Crank relearn must be performed. Us...

    1997 Chevrolet C/K 1500 Silverado Standard Cab LB

    -

    Maintenance & Repair

  • 1998 Chevy k1500 Misfires right after starting 5 answers

    For the past 2 weeks every time I've started my truck it misfires and runs rough for about 15 seconds and then smooths out and runs just fine. Spark plugs, wires, distributor cap and rotor button ...

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

    -

    Maintenance & Repair

  • 1999 Chevy Suburban STILL not running 10 answers

    1999 Chevy Suburban k1500 138,000 miles 5.7 L Vortec engine vehicle was driving perfectly, accelerating smoothly, plenty of power prior to this, even driven that morning. stalled at red light on 11/1...

    1999 Chevrolet C/K 1500 LS 4WD

    -

    Maintenance & Repair

  • 1994 Chevy C1500 5.7 bogs/backfires when I give it gas. 35 answers

    My truck bogs down (and tries to die) when I give it gas to accelerate off of a stop. There is often a backfire or two when this happens. Pumping the gas does not help. I basically have to crawl thr...

    1994 Chevrolet C/K 1500 Silverado Standard Cab Stepside SB 4WD

    -

    Maintenance & Repair

  • 98 Chevy c2500 5.7 check engine light and shudders when i turn right 8 answers

    My truck just threw a multiple cylinder misfire code (PO300) and when I turn right. and only right it shudders. It feels like its not getting enough gas. Ive changed multiple parts( 02 sensors, egr, f...

    1998 Chevrolet C/K 2500 Silverado Standard Cab LB

    -

    Maintenance & Repair

Search Chevrolet C/K 1500 Questions

Chevrolet C/K 1500 Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 3,030
#2 John Saffrahn
John Saffrahn
Reputation 2,410
#3 Rowefast
Rowefast
Reputation 1,560
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,297 Great Deals out of 156,238 listings starting at $1,395
Used GMC Sierra 1500
928 Great Deals out of 62,271 listings starting at $1,395
Used Ford F-150
2,882 Great Deals out of 212,656 listings starting at $1,000
Used Chevrolet C/K 2500
241 listings starting at $5,500
Used Dodge Ram 1500
537 Great Deals out of 12,998 listings starting at $2,199
Used Chevrolet C/K 3500
274 listings starting at $6,999
Used Chevrolet Tahoe
809 Great Deals out of 28,674 listings starting at $1,500
Used Chevrolet Camaro
310 Great Deals out of 38,867 listings starting at $1,250
Used Chevrolet S-10
14 Great Deals out of 1,662 listings starting at $1,995
Used Toyota Tacoma
627 Great Deals out of 35,082 listings starting at $2,155