best OBD1 scantool?? Misfire/backfire ? at cruising speeds 65-70

[jrollings]

btw my timing meter hooked up to number 1 plug wire says my idle is 830-840rpms

 

[SkyHighColorado]

so yeah I have a digital timing light. Hook its up to #1. go under the dash on passenger side near blower motor you will find a brown wire(locations vary), disconnect it. adjust the timing light till you get a solid line and take a reading. Then loosen the distributor hold down clamp and gently rotate the cap I think clockwise to advance. You will find out quick as it will run like crap. Some people adjust it by just listening to when the engine is purring perfect. When you rotate the cap and tape another reading with the light the line will have moved some and you just keep going from there. Once you plug the electronic spark advance back in and put the timing gun on the dampener again the mark will be all over the place, this is normal because the computer is advancing the timing. You only need to set the base timing. from my experience watching knock counts on my laptop 0* degrees has the least knocks. I run a jet chip which increases the spark advance even more so in my case 0* is best I believe.

Idle sounds a little high to me. Maybe adjusting the timing will calm it down some. report back.

 

[jrollings]

Any other ideas besides timing? Just am stumed why it bucks/jerks when I let up on the throttle at cruising speeds. Wouldn't have anything to do with the egr would it?

 

[TylerZ281500]

how are you loking at timing, you aim you timing light at the tab on the cover and it should come in line with the balancer and thats where timing is.

 

[TylerZ281500]

also what brand tune up parts where used? ignition module or coil replaced?

 

[jrollings]

Coil nor the ICM look to be new/newish. I was using the bottom timing tab underneth the truck but after a little reading up I found out I should of been using plug wire 5 when I was using #1. Not sure on what brand parts were used. I'm guessing autozone. The wires don't have a name on them.

 

[jrollings]

I'll try timing in from the top tonight. The bottom one just seemed easier to get to.

 

[jrollings]

I did order a new fuel pressure tester with the tbi apapter. Hopefully it'll be here soon so I can see if my fuel pump is getting weak.

 

[jrollings]

Wow, much easier to time when you know what's going on lol. My 454 was at 10btdc. I bumped in up to 4*btdc like I see everywhere. Haven't taken it on a drive yet but it idles much better at right around 600rpm.

 

[jrollings]

Welp, the problem is still present after adjusting the timing