slowintegra92

I tried reseting the ecu with the fuse and with the battery..no effect..except it was hard to restart and when it did i had to give it gas then when it fired it blew out smoke from extra gas..still idled the same and same miss..i tired unplugging the ecu fuse while running it made no difference as well as it running with the MAF or the TPS unplugged. To see if it would go into a "safe" or "base" mode..no difference.

slowintegra92

Update..i tried the ecu reset by the fuse and battery..nothing. I drove it some more today to try and further diagnose the problem and it seems it actually not a prob below 1900 rpm like i thought..with more driving it seems to be a problem when using less then 1/4 to 1/3 throttle. It's actually stuttering and missing at idle and really at any speed as long as you are like only giving the truck enough throttle to keep it at the desired speed..if you give it throttle from the go once it stops the missing of idle it is clean running but misses as soon as you get to speed and hold..same if you are holding speed and it downshifts at more then 1/4 throttle it clears right up..would that help you diagnose any more? Also i noticed that while it is idle and misfiring i can notice the dash lights flicker just slightly..is that just from the low rpm's caused by the miss you think or could a bad alternator cause this symptom with the missing? The alternator is not that old 1.5 years or less and again the changing of the plugs,wires,cap and the intake tube leak amplified the problem? Thanks for all your help its really putting me for a loop..i am trying to find another MAF to test but its not easy to find one to barrow and the new one even online is 694 dollars at the cheapest..lol. Also i found out through part searching that the truck does have a Ignition control module..would that be a possible cause?

Fabrik8

Well, if the alternator was bad, you'd have trouble charging the battery obviously. I would doubt that the RPM dip would cause a fast enough voltage change to make the lights flicker, unless you have more than one problem showing up at the same time.

It's possible that you have a bad module which is causing spikes of current which are making your lights flicker, but it's probably just as likely that you have a bad ground that's affecting the lights and the ECU (or a sensor, etc) at the same time. A bad ground could also create enough electrical noise to swamp the actual signal from analog engine sensors, and when the signal voltage is high enough it would be less sensitive to the ground noise. There are all kinds of possibilities like that.

I'd take a multimeter (a really good one if you have one or can borrow one) and see what the voltage looks like in a few different places while the engine is stumbly, like at idle. Use the local ground wherever you're looking at the voltage so you'll see any voltage problems referenced to the same ground that the electrical devices would use. Just for sanity, check the battery voltage referenced to the chassis ground and referenced to the negative battery terminal (not the clamp at the end of the cable). If you have a cable problem, and the electronics are getting fed from that cable, there could be a difference in ground potential that shouldn't be there. It's actually very easy to check but very hard to describe clearly..

It does sound like a coil or ignition module problem, but I'm still having trouble justifying how those problems would clear up at anything more than part throttle. Normally a coil problem is persistent over the whole RPM range. I still think it's probably a sensor problem.

slowintegra92

Well worked on the hatefull thing all day..i replaced some cracked and dry roated hoses vacume hoses..check the EGR blew threw..seemed fine. Recheck the firing order..i got in the new fuel filter and replaced it..let me tell you it was a bitch..tucked under the intake manifold..had to do it through a hole big enough for one hand through the wheel well..needless to say it runs even better then before over 1/4 throttle but still the same dam miss at idle and below 1/4 throttle. I would love if there was someone local that could check the sensors with the multimeter for the correct values..i am not to sure on that..TPS, MAF and ICU. Bc they all have to be ordered and are 150 for 2 and 300 for the MAF. I dont just want to piss money at the thing not knowing if it will fix the problem...but i relly need my daily back i have done all the basic routine stuff..