Engine Miss
 

I Have A 97' 5.7 Lt. ,in A 2wd. ,short ,extended Cab Pick Up ,
When Traveling At Road Speed The Engine Has A Miss ,like A Plug That Is Fouled, If You Stand On It It Runs Perfect, Or Ideling It Seems Ok.i've Replaced Everything I Can Think Of..throws No Codes On The Computer..replaced:fuel Pump,filter,8-injectors, Egr Valve,cap,rotor,wires,plugs,o2 Sensors,t.p.i.,. And No Good.. Thanks Greg!!

Vacuum leak?

I know I may have some objections to this, but take a look at the coil(s). My nephew had a 99 (blue oval vehicle), that idled good, but when lightly accelerating, it missed, very noticealby. He changed fuel pump/filter. A muffler shop, (that I wont mention), changed the computer, but the problem continued until someone recommened changing the coil. The coil was the problem. Hope this helps.

I have a 1998 Silverado Ext Cab w/5.7L and am experiencing similar symptoms. I usually get the miss or surging while in overdrive between 1400-1800 RPM's (40-50 mph). If I push on the accelerator or get out of that RPM range, it goes away, or at least I don't notice it. ?????? I was initially thinking fuel pump/pressure but it seems that may not be it by the responses. Tranny maybe???

my 97 5.7L does that occasionally too. I have been wondering about this for some time.

How many miles?
 

If you have over 65-70K, replace the plug wires and ignition coil. If it's less than that, look closely at the coil between the frame and the molded windings. If you see any white or burnt looking spots (very likely), replace it, and use the best one you can find. Nearly any "tuneup" I do these days includes a coil, based on experience. :cool: