Just as the title says, for the last few months I have had an intermittent bogging/stumbling with some backfiring during light acceleration, if I mash the pedal it picks right up or dies even further. I am not super knowledgable about trucks and my mechanic does not know whats up. Recently I replaced the cat converter,PCV valve and TPS sensor.

I would like to fix this myself could anyone guide me where to start.? I looked fro vacuum leaks but have not had much luck there, I also checked the plug wires the look ox none are running paralell or anything.

Thank you for any help, there is such a wealth of knowledge here I am sure someone can help.

Regards, Pete.

 

as a troubleshooting tip for vacuum leaks, temporarily disconnect all vac hoses from the intake and cap off the ports on the intake. mark each hose so you can put them correctly, and be aware that you'll have a lot of vacuum operated stuff that quits working, including power assist brakes.

if the stumble goes away, you're on the right track. add the hoses back one at a time until you find the culprit. if the stumble remains, then its not vac. at least, not a normal, minor vac leak.

backfiring indicates your getting spark back into the intake and throttle body, a place its not supposed to be. could be timing problem, plug wires misplaced, or cross firing, cam position sensor, crank position sensor, badly leaking intake valve.

 

what year is the truck?

it sounds like a misfire. when i crossed all four wires on one side (read the firing order written on my hand upside down) it idled fine but when i revved it up it backfired like a 21 gun salute.

with the plug wires you want the 5/7 and the 6/8 wires away from each other. if they are close, and causing a problem like yours then you probably have a cracked wire. run the truck in the dark with the hood light unplugged and see if you have any crossfire on the plug wires (spark arcing from the wire insulation).

check the condition and gap of your plugs.

make sure your plug wires snap onto the plugs and the distributor cap.

pull the distributor cap and check the condition of the contacts on the inside of it and the condition of the rotor button.

 

it is a 97 190,000 miles.

 

97 means that you should get a CEL if it has a misfire because it is OBDII.

have you fixed your plenum gasket yet?

 

i get CEL that comes on for a day or three then goes out. This happens once every 2 months or so.

My OBD codes are #43, peak dwell time not met and #12 current to ecm interuppted in the last 50 cycles.