[Sontizzle]

would the map sensor being bad cause 3 cylinders on one side to miss fire? i gettin codes that cylinders 2 4 and 8 are miss firing (something about injector circuits) or would it be something with the ECU?

i put a test light on the injectors and they are getting power.

[greasefingers]

Originally Posted by Sontizzle

would the map sensor being bad cause 3 cylinders on one side to miss fire?

No

What do the plugs look like? WHAT year and engine do you have!

[Sontizzle]

Originally Posted by greasefingers

No

What do the plugs look like? WHAT year and engine do you have!

its a 96 limited grand cherokee with the 318 (5.2L). the plugs are covered in gas due to it miss firing.

[greasefingers]

I would start with a general tune-up: wires, plugs, cap, & rotor.

[Sontizzle]

Originally Posted by greasefingers

I would start with a general tune-up: wires, plugs, cap, & rotor.

it has all that new along with fuel filter. i got it scanned today and it said MAP sensor HIGH INPUT and something like cylinder circuit mis fire in cylinders 2 4 and 8.

[greasefingers]

Originally Posted by Sontizzle

it has all that new along with fuel filter

You should have included all the inforamtion in the first thread then.

[greasefingers]

Originally Posted by Sontizzle

got it scanned today and it said MAP sensor HIGH INPUT and something like cylinder circuit mis fire in cylinders 2 4 and 8.

Well that’s really weird because the intake manifold is the same pressure everywhere under there. So if the MAP is bad then why would the PCM only respond well to one side and not the other? I guess you have to replace the MAP and see. They are cheap.

[Sontizzle]

ok i think these are the codes it pulled:

P0204: injector number 4 control circuit.
P0206: injector number 6 control circuit.
P0208: injector number 8 control circuit.

and i think the MAP sensor code was P0108

[Sontizzle]

Originally Posted by greasefingers

I guess you have to replace the MAP and see. They are cheap.

100 bucks isnt cheap in my book! lol

what is a control circuit for an injector? ive been searching through my haynes manual and cant find anything about it

[greasefingers]

For some reason, maybe MAP related, it appears that the PCM is leaving the injectors open too long and causing a Rich condition.

[greasefingers]

You can get a MAP for your model for $ 61 from rockauto: http://www.rockauto.com/catalog/x,ca...,parttype,5124

[Sontizzle]

Originally Posted by greasefingers

For some reason, maybe MAP related, it appears that the PCM is leaving the injectors open too long and causing a Rich condition.

PCM? is that that computer? do u kno where the injector control circuits are located?

[greasefingers]

Yes ecu (electronic control unit) = pcm (powertrain control module) = computer

What do you need to know about the injector circuit? The pcm uses many sensors to determine the duration (hold-time) of each injector. The circuit is difficult to discuss over the WorldWideWeb. Basically, the injectors always have power supplied and the pcm grounds the circuit. The computer can be considered a digitally grounding switch, among other things.

[Sontizzle]

so basically your sayin to change the map sensor 1st and if that doesnt work then try the ecu?

[rm2001wj]

Pull some of the other plugs and take a look at them. A bad MAP sensor would make all the cylinders run rich, but not necessarily rich enough in each cylinder to create continuous misfires in every one of them. I'll bet the other plugs will have sooty carbon deposits indicating a rich mixture also.