98 cavalier rough idle

1998 CHEVROLET CAVALIER
205,000 MILES • 4 CYL • FWD • AUTOMATIC
Avatar
ULLYCEESE
  • MEMBER
  • 4 POSTS
1998 cavalier 2.4l engine, at idle speed it is normal, then 20sec at idle it starts to sputter, and idle very rough. However there is no lack of power while the car is moving. Did a compression test, all normal, replaced camshaft and crankshaft position sensors.changed spark plugs and the tiny wire connectors,still acting crazy, there is no check engine light. any ideas?
Mar 20, 2011 at 6:49 AM
Advertisement
Avatar
JDL
  • ✓Experienced Mechanic
  • 16,098 POSTS
Clean the throttle body and iac. I always check for codes, regardless of lite, just habit, I guess. How long since a tune-up?
Mar 20, 2011 at 8:23 AM
Avatar
ULLYCEESE
  • MEMBER
  • 4 POSTS
tuned up in oct 2010. changed iac, tps, crank sensor, cam sensor. checked both o2 sensors, ran injector cleaner through it got better for a day, but not perfect. now back to same old thing as before rough idle when stopped. but a code did come up as bank1 running rich. any ideas?
Mar 21, 2011 at 6:42 PM
Avatar
JDL
  • ✓Experienced Mechanic
  • 16,098 POSTS
Use a fuel pressure gage, see if pressure holds after pump stops. If no schrader valve, some models, you may have to use a special fitting to use gage. I can't remember without looking?
Mar 22, 2011 at 7:23 AM
Avatar
ULLYCEESE
  • MEMBER
  • 4 POSTS
try this test, start the car, let it run for about 1min then shut it off, remover the vacuum line from the fuel pressure regulator and look for fuel in the vacuum line, there should not be fuel present in the line if you see or smell gas in it, then the regulator is bad. My 2.4l did this to me also, it would rough idle and try to stall sometimes. dealer wanted to take the engine apart, i said no way and spent 6o bucks on dealer manuals from ebay.
Sep 28, 2011 at 5:11 PM
Avatar
JDL
  • ✓Experienced Mechanic
  • 16,098 POSTS
Sounds good to me.
Nov 16, 2011 at 1:13 PM
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