yardpro

So the last 24 months I really haven’t driven my87 very much. I’ve been really frustrated with the surging.

when I first start it, it isles fine.
after a few minutes it begins to hunt with Roma surging up and down and will sometimes die.

when driving it does the same. Sometimes when I approach a stoplight, etc, it dies when i let off the gas.
this is becoming a little dangerous.

also when I floor it it feels a little sluggish then suddenly like a switch it gets more power..(nothing to do with rpm in the torque curve).

i replaces the o2 with new ones from roger but no difference.

maf?

NickTucker

This can be a lot of things.. I had a similar issue on my '88, idle hunted all over the place and died here and there. Turned out to the LH module. Had it rebuilt and everything is fine.

I am sure others will chime in but a few things come to mind:
- False air. Make sure all vacuum lines are good. If you have not top a top end refresh it might be time.
- Ignition.. Wires, rotors, caps, plugs.. check them all.
- Sticky ISV.. Search for the "WD40 Trick" for that one....

Good luck!

The Forgotten On

Get out a can of ether and start spraying around the intake to check for vacuum leaks. I had the same issue and it turned out to be both hoses under the intake to the ICV had failed and cracked.

I also replaced the MAF and 02 sensor at the same time due to not being sure what could be wrong, but also needing to replace them as they had 200K miles on them...

I would start with the easy stuff which is around the intake. Dropping the cat is a much bigger pain to me than taking the intake off for sure.

dr bob

If the LH is original, replace it. And fix the vacuum leaks. If the LH has been replaced, fix the vacuum leaks.

worf928

Check that the idle switch is working when the engine is warm.

What is the history of the crank position sensor?

yardpro

idle switch is good

i do have a vac leak in the blend door actuator, that is next on my list.
Ill try capping off the vac line that feeds the hvac to check.