Engine hesitates off idle

[Keith M]

Looking for some direction on how to diagnose this.
87i m/t was rebuilt a couple of years ago. Replace all vacuum lines along with the cps and o2 sensor.
It idles and runs fine, but it hesitates, or maybe a better description would be, it stutters just off idle when I push the accelerator. I found a shop just up the street that can do a smoke test if it is a vacuum leak issue or is it something else I should be looking at?
Thanks in advance

[E30Gus]

Same problem here. I'm getting a hold of another known good AFM to swap in and see if it fixes it. I've read that the AFM's can develope "dead spots"

[BergerNJ]

I think it might be the throttle cable..make sure its tight....I read a thread not too long ago about someone randomly making sure theres was correctly tightened and it made the motor respond much better

mine also has a dead spot but it will hesitate right off idle but pick up in like half a second..I havent messed with that issue yet because of other problems and possible vac leaks still

[Jafxod]

What is your idle at. When my idle was at like 550rpm on my m50 it was like that, i adjusted the cable till it sat at 750 and no more issues.

[Keith M]

Mine idles at around 700 rpms. I will check on the throttle cable and swap out the AFM with another I have.

[nomansland92]

same problem here with a bad hesitation.

So far i have

new intake gaskets
checked all vacuum lines and possible leaks
new pulse sensor
new cts
new o2 sensor
swapped afm
new injectors
upgraded from 151 to 173 ecu


Still no luck finding my problem but good luck with yours haha

[5Toes]

I think it is just the motor.. I have the same problem.. throttle cable might be a little too tight.. lol

[djdropit]

I have a similar issue on an M20. Idles fine, but stutters with the slightest bit of gas only to go back to normal if I punch it to above 1000 RPMs instead of ease into it.

I just replaced the TPS, but I know I have a blown head gasket. With white smoke and 3 of 6 cylinder chambers below normal pressure. I have a rebuilt head ready to go on, but it would be nice to diagnose this before I put it on.

[Keith M]

It seems to be a common problem. I swapped out the AFM and checked out the throttle cable, even changed the ecu for good measure. I still think I have a vacuum leak somewhere. Smoke check is the next step for me. Might take a little while to get it done but I will report back.