Next step in hesitaion issue?

[wolf76]

Hello all. I have been chasing down a hesitaion issue for some time now and I'm seeking advice as to what I should do next. I have an 84 that presents a hesitaion/surging at around 3000 rpm. It used to happen at crusing speed in any gear but that was solved by replacing the cylinder head temp sensor. It now is present maily in 2nd when I'm accelerating but goes away if I keep my foot on the gas. It is very noticeable when I'm going uphill. It is now also only evident in 1st and 2nd gears. What I've done so far:

1. Replace all plugs/wires/cap and rotor
2. Replace fuel pump and filter/air filter
3. Replace speed/reference/cylinder head temp sensor
4. Check for vacuum leaks
5. Techron and Seafoam treatments


I was thinking of adjusting the wiper arm on the AFM next. After reading some posts here people who had similar issues have also replcaed the O2 sensor and the throttle position switch. I was just wondering if I should procede with the AFM or if I should try one of the other 2 ideas first.

Thanks,

Chris

[Tim L]

It sounds like your mass air sensor.

[wolf76]

Thanks Tim. Do I have a mass air sensor on the 84 or are you referring to the air flow meter?

Thanks,

Chris

[Tim L]

Yes, there is a lot of info here on the problems with air flow sensor. Does your car serge when accelerating?

[dtxscott]

He's referring to your AFM.

[wolf76]

Tim-yes it does surge slightly, as though the information it's getting on what to do is not accurate. I was just wondering if my symptoms are more specific to something else. I will replace the o2 sensor anyway since it's probably due anyway. Also, do I need to reset the mixture or anything else after the afm is adjusted?

Thanks,

Chris

[dtxscott]

Do your valves need adjusting?

My car was doing this very slightly before I did a tune up with plugs, cap, rotor, O2 sensor and valve adjustment.

I think it was leaning out at light throttle cruising and would appear as a surge.

I would seek the AFM spring as a last resort.

[wolf76]

Thanks Scott. The valves are good. So you recommend the O2 sensor before the AFM?

Thanks,

Chris

[dshepp806]

Maybe mix, in the end.

For now, easy enough to verify the idle position switches' functionality. Make sure that AFM is dead cleaned and lubed.......dirty/pitted traces within the AFM contact area could be the culprit but do the simple first.

Then, onward.

Best,

Doyle

[wolf76]

Thanks Doyle as well as everyone else that responded. Will try the O2 sensor and adjusting the AFM. Hopefully one of the 2 will fix the problem, if not on to the throttle switch.

Thanks,

Chris