Idle problems in 5.0 99 ford

[jamaca85]

So I seem to have an idling problem in my 5.0 when the motor starts up motor starts shaking like it's missing but it clears up after 12 1300 RPMs and you give it gas but when it comes back down to idle it starts sputtering and trying to stall again we have changed everything from EGR valves cam sensors checked every fuel injector did voltage readings on everything compression check and it still has the same problem . We also checked the fuel pressure fuel filters and everything is okay

[HoovDaddy]

Vacuum leak?

[jamaca85]

We already covered that no vacuum leaks actually replaced all the vacuum lines on the motor but thanks

[ID67goat]

Wasn’t the last year for 5.0 in 95?

A couple ideas…. have you verified your timing? Have you checked the idle air bypass valve for proper operation? They can get plugged up. Also mass airflow meter can have issues….

[jamaca85]

yes we have checked both..the idle valve is working and not plugged, mass air sensor has been replaced...thats whats so weird about it. we have gone from gas tank to injectors still has the issue. ran fine till he parked it for a week then issue started. the odd thing is it hasnt thrown no codes

[FrankieT/A]

Did you replace the battery or disconnect it recently? If so it may need to relearn the idle strategy and may require about 20 key starts.

[jamaca85]

thanks i will ask him

[jamaca85]

Yeah I'm hoping that somebody has run into this issue with the same symptoms with with no check engine light and has solved it

[Jay S]

That is a pretty common problem on fords that era. Been a while since I worked on those but if I recall correct the issue is up by the throttle body at the AIC. It requires disassembly and cleaning. There should be how to videos on you tube. Look up Ford idle air control valve. It causes a big dead spot coming off idle if it doesn’t work or is slow. If it is bad a check engine light will come on. If it is gummed up and slow the check engine light will likely not come on.

[necdb3]

Stupid question, is there a K&N filter on there? The reason I ask, I worked at a Ford dealer for years and the open K&N filters would disturb the MAF sensor because of the turbulence from the radiator fan. If there is, try installing the factory filter box and see if it corrects the issue. You could put cardboard to block the wind turbulence to test it.

[necdb3]

What wound up being the problem?