3.4l, 108000 miles. gas mileage was 25mpg. cel lit up. o2 sensor code(pre cat). replaced sensor. decided to replace plugs and wires for maintenance while replacing o2. after new parts were installed mileage dropped to 17 mpg. no cel light now. idles ok. when pressing throttle halfway engine hiccups every few seconds. rechecked plug wire connections and firing order. looked for loose vacuum hoses. I did spend 2 hours jerking on the old rear plug wires to remove them. anything back there i may have dislodged? It still runs on the road, but i have noticed a slight power loss. replaced plugs with ac oem's. wire set from advanced, silicon 7?mm, about 25-30 dollars.
Thinking of getting obd reader actron 9185. any links to a review of this scanner?

What was the original code number you found?




78 Corvette Pace Car For Sale-18k mi orig-Florida

p0135

That was just a heater code so that had no effect on your engine. It had to be something you did while changing the plugs and wires. You may have cracked a plug or crossed the plug wires.

Check your firing order first. If you find nothing, pull the plugs back out and look at them closely for any cracks.

2002 Chevrolet Venture
3.4 liter V-6 VIN "E"






78 Corvette Pace Car For Sale-18k mi orig-Florida




(This post was edited by Hammer Time on Jul 5, 2009, 2:39 PM)

I've also had probs with dirty MAF sensors that would give those problems but not code.... A can of mass air flow sensor cleaner & everything was good....


Man I can't tell you how much diag work K&N filters have given me...... GM has a TSB out about oil filled filters voiding warranties now......


(This post was edited by Sidom on Jul 5, 2009, 5:10 PM)

I'll pull the plugs tomorrow. firing order is ok.
bad wire? throttle body has some varnish in it. it seems to me that van runs too good for a hard miss or crossed wires.

It would appear that whatever happened, happened when you changed the plugs and wires.




78 Corvette Pace Car For Sale-18k mi orig-Florida

cleaned maf. pulled plugs. all looks good. drove 20 miles. no change, still hiccups constantly at half to full throttle. under half throttle no hiccups. need live scanner on van while hiccupping? no cel light while hiccupping.

Chevy; Drinking a glass of water up-side down usually will cure the hiccups. The PCM should pick up misfires and store a trouble code. That is puzzling. As Hammer suggested, it is very easy to crack the porcelain on a spark plug while tightening. Don't forget to check the gap on the plugs when you remove them. Possible that you got some grease/dirt in between the plug electrodes. Use dielectric grease on the plug boots when re-installing.
Loren
SW WA

Plugs ok, no cracks, gap .060, color is good. catalytic plugged/restricted? Vacuum test work on Venture? There is a port on the intake plenum.

No, a plugged Cat won't act like that but if you left any hoses off the intake or if the snorkal is leaking anywhere, it will do that.




78 Corvette Pace Car For Sale-18k mi orig-Florida