I have had some problems with my 98 chevy truck with a 5.0. It started out where I had rough idle when I would come to stop lights, seeming like it would load up with fuel. I took it in and they said I had a bad MAP sensor and post cat 02. I took it home and replaced them and cleared the codes. Then I got these codes, P0151, P0300, P0507, P1153. I checked the right bank plugs and they were fouled, replaced but didn't fix the rough idle. Replaced the right bank 02 and cleaned the idle control valve, now runs much smoother, but still a fast idle in park 1200-1300 rpm. It will idle fast in gear coasting as well. Code P0507. Any ideas on the fast idle??
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Have you tried changing the distributor cap and rotor? These tend to get moisture build-up and cause a slight cross-fire, usually most noticeable at idle. They are also very common for intake manifold gasket leaks, but they usually start out as a coolant or oil leak at the corners of the manifold.
Sounds like it could be a dirty or faulty idle air control valve.Take it off and clean it with a wire brush and a non-chlronated brake cleaner or replace it with a new one.Make sure you reset the computer after cleaning or replacing the valve.
If it has not pulled any codes (idiot light). Clean your throttle body, and change your spark plugs with A/C Delcos #41-103, most other brands will cause rough idle like Autolites and Bosch. This would be a cheap way to fix this problem.
If by chance you have just recently changed the battery or had the battery unhooked. Let me know, it's an easier fix that costs virtually nothing.
If it does not do it in park or neutral, it could be a number of things. One being a sticking Torque Converter Clutch solenoid (TCC). It could be that it needs a simple tune-up. How often does this problem happen?
I need to know the codes so I can properly diagnois your problem. Here are a few tips though. Your electronics inside the transmission may be going out. You should start by changing the fluid and the filter. Let me know if there is a lot of metal or fiber shavings in the pan. Put new fluid in and clear your codes. See how it shifts and then let me know what is going on with it. Hope this helps.
I had a similar problem on my "93 Ford probe. The engine idled pretty rough with shakes, Turned out to be a head gasket leaking engine coolant into the cylinder during low rpm's. At fast rpm's it was fine becuase the internal cylinder pressure was greater than the hot coolant pressure & would prevent the coolant from leaking in.
A friend has the same problem with his "94 Blazer 4.3 L, throttle body injection, manual tranny. He hasn't fixed it yet, It started a few weeks ago & is getting worse. His gets a fast idle with hiccups which causes the engine shake. He already checked the EGR valve. He also has a severe exhaust problem, Not oilly but very gray & terrible smelly, but only when the fast idle problem happens. THis fast idle hiccup problem starts when the engine is warmed up.