'miss' at lower rpms...

[adam74]

tahoe has what feels like a miss at acceleration up to about 3k rpms after that clears out and runs real smooth until it shifts, then back to a 'miss'. wouldnt think it would be plug or wire due to fact it does go away. any ideas?

 

[lesterl]

Cap, Rotor, Coil, Wire, Plug, Injector, Fpr, Rings, valves.....

 

[IronMan4Real]

start with tune up...stick with all GM parts.IMHO

 

[adam74]

did the fuel filter, plugs, cap and rotor already. plugs next

 

[IronMan4Real]

do the plugs...and did you use 100% GM parts?

 

[samotahoe]

scan for codes, if no codes or you get a p0171 its going to be maf sensor

 

[adam74]

ac delco plugs but oreilly rotor. no codes when using paperclip method to check.

 

[samotahoe]

if you have access to a scope, I would test the mass air flow sensor. could be the problem since there are no codes

 

[adam74]

dont have one but will check it out somehow. thanks

 

[lesterl]

You can buy a can of MAF sensor cleaner to clean it, also you can unplug it and the PCM will attempt to idle the engine with MAP sensor readings instead......

 

[adam74]

wait now that Im thinkin bout it I dont have a maf its a 95 tbi 5.7

 

[lesterl]

Yeah, if your rig is a 95, then yeah you have no MAF, check for EGR leakage perhaps? My missfire low rpm was fixed on my 95 with an Accel super coil and regapping the plugs a little wider (replaced cap, rotor, plugs before)....... Got the coil off amazon.com ACCEL 140011, also noticed inside of my tailpipe cleared up (black residue gone).....

 

[adam74]

i replaced vacuum hoses for the egr but hadnt looked at the egr itself. got a set of ac delco wires to put on and will check the egr at the same time..hopefully this weekend I will have time.

 

[lesterl]

If you have a 95, check the Base gasket on the TBI, if the EGR needs replaced you MUST buy an AC DELCO unit, dont ask how I know that.... POS aftermarket universal crap......

 

[adam74]

ok Ill check that also. thanks

 

[rockenthebowtie]

@Adam not do much the EGR itself but the EGR vacuum control solenoid they have a tendency of hanging up and allwing to much vacuum to the EGR.. you can test it by disconnecting the vacuum supply to the EGR and putting a little screw in the vacuum hose to plug it and drive it see what happens... if that help start whith the vacuum control solenoid

 

[adam74]

That the one that has two poerts? Only one hose is hooked up to it. Judging by the diagram on the core support I think its says its a vent, is that correct?

 

[rockenthebowtie]

Yes one is a vent only it should have one coming from the throttle body and one to the EGR valve.. the vacuum control solenoid should have a total of 3 ports 1 of them being the vent

 

[adam74]

So the vent ports have no hoses hooked up to them correct?

 

[rockenthebowtie]

Correct