Which Coil for my '99 5.7 Vortec.

[Big Poppa Pump]

I have a '99 Tahoe that I have replaced the cap, rotor, wires, plugs and fuel filter. If I'm pulling a load or just pushing it at highway speeds up a long grade I will feel that I'm not getting all of the power and will set off the check engine light for cylinder mis fires. I'm wondering if a new coil may help. The only upgrade on this truck is a cold air intake. What do you all recommend. I saw these three.

 

[RED TAHOE LS]

Did you use AC Delco plugs ? if not, JMHO, change them. You may have a cracked plug. Plugs will tell on you in a STRAIN or long incline. Good luck to you.
David g.........

 

[east302]

Which code are you getting...is it for a random misfire (P0300) or a specific cylinder (P030#)?

If on a specific cylinder, swap the plug on that with another cylinder, see if the code follows.

I'd go with an ACDelco. They have different qualities of parts--advantage, professional and OEM/dealer. Go with the Professional or OEM if you can. Advantage is their lower end and probably not much different than a parts store brand...manufactured by someone else with Delco's label slapped on.

 

[Big Poppa Pump]

Thanks guys. I have the OEM iridium plugs. The misfire is random. I'm going to pick up the OEM AC Delco coil from Criswell Chevrolet or if they won't give me a reasonable price I'll buy it off Rock Auto for $35 plus shipping.

 

[Big Poppa Pump]

Replaced the ignition coil with the AC Delco D577 part from the dealership. Huge PIA due to the wiring harness bracket. It did not cure the lack of power on a grade but I have not gotten a check engine for random misfires.

 

[Big Poppa Pump]

There is an improvement but what are the best/recommended plugs for the 1999 Tahoe with the 5.7 Vortex?

 

[Big Poppa Pump]

Ugh. Still have the misfire and slight engine shake and loss of power when getting into it on long inclines. I'm wondering if I need to do the spider install. I watched a 36 minute youtube video and it looks relatively difficult with all of the stuff you have to get out of the way.

 

[TigerEyz3]

Could be cap/rotor... moisture is not our friend. ACDelco (professional or OEM) is better than other branding. If looking at coil, ACDelco (professional or OEM) is good, but other brands can be substituted.

Fuel spider replacement is a great improvement over OEM...quite a bit more involved with that project compared to replacing cap/rotor or coil.

 

[RED TAHOE LS]

One thing you might consider, especially if it's got high mileage, the exhaust, either the convertor or muffler. They have been known to partial restriction causing your type of problem. If you still have the factory exhaust
you could loosen the converter and secure it to do a test run, you may just find your problem. Good luck.
David g................

 

[bigfootchiro]

Check compression and the distributor itself. You may have a worn distributor gear.