1988 GMC Sierra Engine miss

1988 GMC SIERRA
125,000 MILES • V8 • 2WD • AUTOMATIC
Avatar
MIKE.JANES
  • MEMBER
  • 1 POST
I changed plugs, wires, cap, and rotor. Engine still misses. At idle you can hear it missing, and it makes a popping sound in the exhaust. By pulling plug wires one at a time, each one seems to slow the engine down and it idles rougher. Engine misses while idling or going down the road. It also misses under acceleration whether mild or wild.

Any Ideas?
May 5, 2010 at 1:27 AM
Advertisement
Avatar
RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Engine running rough or misfiring can be cause by the following:

1.Defective spark plug.
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.
10.Throttle position sensor
May 5, 2010 at 2:14 AM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle