Mechanic recommendations

[Redgrom]

Trying to figure out a lurching issue when the truck is cold. Doesn't feel like a transmission issue and it's not throwing any codes and I've done a tune and checked the obvious stuff. Can anyone recommend a mechanic in southern Orange County or norther San Diego area? Running out of things I know to check and don't really want to take it to the dealer

[Seabass]

No input for a mechanic.

Surging under load or just at idle? Does it ever miss? Does the idle move around when not in gear? Year and 302 or 351? When you did a tune up what did you do? plugs, wires, cap and rotor?

Things I suspect could cause surging or stumbling would be idle motor if its just at idle of course. If its under load a weak or retarded spark would make it feel like your losing power and then getting it back. This could be a weak coil, ignition control module (common failure) or a pip sensor which is in the distributor (cam sensor, also somewhat common)

The 5.0s had knock sensors that could play into it as well butI have no experience with them.

[Rmc]

Iac valve? I think that's what it's called. I gotta look at the book it's been a few since I worked on one. It's idle air control valve as memory serves. This will cause the rpm surging issue while at idle.

[damon1272]

Probably iac. A quick way to tell if your vehicle has a learned idle is to unplug the iac. If the truck struggles to maintain idle or dies then I would make sure the throttle body and iac are clean and then reset the computer and do an initial drive to set parameters. ie five minute ie with lights on and a five mile test drive letting the computer see at least one good fairly long wot.
One other item to check is if you're have sufficient wire separation on your plug wires to prevent cross firing cyl

[rdcjuanb]

The dad of the southwest dude is supposedly really good. Did Cyphers bronco and some others. No experience myself. Just heresay.

[robertcrav]

Mark Sr at Southwest is good at diagnosing/trouble shooting

[DMbronco]

plus one for Mark Senior.

[Redgrom]

Thanks for the help! It only occurs at slow speeds and generally under 20mph. Especially noticeable at low Rpm's, was considering changing the coil and see if that helps since it's the only thing I didn't change when tuning (plugs, wires cap/rotor) I cleaned the throttle body but didn't go nuts just got what I could easily access. Also it's a 351 with just over 155k if that helps, still kinda new to me and very slowly planning a full build but just driving it around town for now enjoying a convertible truck.
If the coil doesn't solve my issue I will hit mark up.
Thanks!
Brent