what could cause a miss at light throttle and wot when i have delteg ingntion and have a complete tune already done. the miss at low rpms is not heavy vary light miss and the miss at wot and is there only sometime(never constant), when it does back fire its through the intake.Put vacume gauge on checked all good at a 18 in. i have done a timeing light test and the light never flashed constantly. fuel system good pressure and injector plus is good.If you guys have any suggestion to what to try next tell me. On one more thing when free reving its perfect buttt when you rev to 1300 and 2000 it acts like its dropping a cycl. Also in the morings when you start it to warm up it misses and kinda stutders

 

what type of plugs are you using?

How many miles are on the plugs?

how long how you had the Delteq?

 

ac rapid fire plaugs 2500 miles on plugs, have had the delteq for 6 mouths

 

forgot to say that the mpg only about 190 miles to a tank.Would not have the egr vavle and air pump make that big of a diffrenets. the car has always had that kind of mpg even with new bosch o2 sensors

 

did you gap the plugs to the correct gap? With the engine running, can you see the red light on the opti box? It should be steady on, no flashing. How old is the opti?

removing the egr and smog pump does nothing to increase performance. it only reduces wieght. removing the egr is not a good thing. it is to lower the combustion temps at cruse speed only. This will lower NOx.

 

You could always pull off the EGR valve and take a look at it and clean it. I know there is either a TSB or I think it's actually a recall on some EGR valves on some LT1s, search and you should find one of my old threads on that.

Also, I had a similar miss problem with my delteq a while back. I installed the system on my car and it ran perfect for a few months, then I started to get misses like the engine was cutting out and backfiring through the intake manifold, only at certain rpms and usually when warm. When I put the car back to stock, without the Delteq it went away, but as soon as I put the delteq back on, boom. Long story short, after swapping every part out only to find out the problem was still there. I took a stab in the dark and replaced the opti with a new GM one. (Not that I don't use GM ones in the first place ...) Problemo gone. I then later went to open up the opti and completely inspected it visually, not ONE thing wrong, perfectly clean, no bearing problems, no rust dust, no oil, no carbon build up, perfect. but it did solve my problem.

-Zach

 

the opti spark has a good 5 years of it and prob. about 20,000 on it and also the egr is still on the car just not hooked up. One more question what do you think about bosch o2 sensors???

 

Just to let you know, my opti, when I decided to wing it and replace it, only had about 10k on it, and was about 1.5yrs old.... go figure. As far as bosch a/f sensors, ive had problems with them in the past. I went with AC Delco sensors, about 30bucks a piece through gmpartsdirect.com

 

Im going to check the injectors frist the make sure its not a pluged or bad injector the i will rule out that then move to the opti hopefully its a bad injjector