2.5L Idling Rough and Stalling
My 99 2.5L Ranger will run fine above idle but at idle it runs very rough. Sometimes when coming down to idle it will sputter badly and stall. It always starts back up but sometimes takes a few tries.
The ecu threw codes for bank 1 lean and bank 1 misfire. So far I have replace the plugs and wires, swapped the coil packs, replaced the injector in bank 1, cleaned and tested the IAC valve, and cleaned the MAF. I cleared the codes but haven't given it a chance to see if the code comes back. I am not really sure what else could cause these symptoms. Bad EGR Valve? Thanks for any help or suggestions you can offer. |
Re: 2.5L Idling Rough and Stalling
bad egr should throw a code. check your intake gaskets and throttle body gasket. I don't know if a vacuum leak could cause this.
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Re: 2.5L Idling Rough and Stalling
I have checked for a vacuum leak using starter fluid. Could that same test check the gaskets?
I just put a vacuum tester on the EGR valve and it won't hold any pressure. I think I should replace it. Even if it doesn't solve the problem it probably isn't working. |
Re: 2.5L Idling Rough and Stalling
Same method will work for gaskets. I'm not familiar with this test for the egr. Could you elaborate on this?
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Re: 2.5L Idling Rough and Stalling
The EGR valve should hold a vacuum when applied by a handheld pump.
Example This is the pump I used I just put on a new EGR valve. I tested the old one after I took it off the truck. The valve wouldn't move when a vacuum was applied and it was stuck partially open. Unfortunately the truck still idle's badly but the other tests on that first link now work correctly. I forgot to mention earlier that the fuel pressure tested good. I did my best to spray around the head gasket but didn't notice any difference. If the gasket was leaking, how noticeable would the change in RPM be? What else could I try? |
Re: 2.5L Idling Rough and Stalling
Using my scan tool I noticed that the O2 sensor after the cat doesn't register any volts until after the engine is warmed up and even then the values are way lower than the sensor in the exhaust manifold. Could it be bad? I tried to get it out to replace it but its rusted in there pretty well.
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Re: 2.5L Idling Rough and Stalling
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Re: 2.5L Idling Rough and Stalling
Above statement is correct. 2nd O2 sensor should only register after the cat is heated up and functioning. The signal should be different because the stream should chemically change after the cat.
When you said head gasket you meant the intake gaskets right? that is why I specified because that would lead to excess air into combustion chamber that MAF did not account for. |
Re: 2.5L Idling Rough and Stalling
Sorry I haven't responded sooner, I work long hours during the week.
Yeah, I was spraying around the head gasket, which doesn't make sense now that I think about it. I will try to do as you recommend, probably tomorrow after work. I coworker who had similar problems on his 2.3 ranger said he fixed it by disabling the IAC and setting the idle manually. Is there any merit to that? ---------- Oh another thing, since I changed the fuel injector on bank 1 the running lean code has not returned. Looks like I have (Had?) multiple problems. |
Re: 2.5L Idling Rough and Stalling
I would say your maf is not working properly.
This will cause all the all the issues you are having. |
Re: 2.5L Idling Rough and Stalling
No it does not ping. I have noticed that when I first start the engine it idles very smoothly. It only runs rough after returning to idle after driving or revving the engine.
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Re: 2.5L Idling Rough and Stalling
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Re: 2.5L Idling Rough and Stalling
So I just went out and sprayed starter fluid on the lower intake gasket. When I hit a certain spot the RPM's went down and it struggled to run a bit. Isn't that counter intuitive? Does that mean I need to replace the intake gasket? I think I am going to test it again as I ran out of what little starter fluid I had and couldn't do a through test.
Also, I got a cylinder 2 misfire code today. Thank you all for your help so far. |
Check plug wires
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