Check your igniter control module (ICM)
Bogging down under acceleration... MAF? Throttle Body? Something else? Asking for input (1 Viewer)
- Thread starter 67cruiser
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I skimmed through the thread but did you ever check the resistance of your O2 sensors? Last year I had issues passing emissions here in AZ. I had high CO/HC issues and that was a direct reflection my bad O2 sensors. The factory FSM says they should be 5.5-6 ohms. Is there black soot around your tailpipe? The bogging might be a fuel delivery issue, too rich/too lean. There might be some other underlying issues as well.
What is the condition of the injectors, wire harness near the EGR? In my 94 I was having a hesitation as well. The wire harness was the issue and while I had the harness out I had the injectors cleaned and o-rings replaced.
What is the condition of the injectors, wire harness near the EGR? In my 94 I was having a hesitation as well. The wire harness was the issue and while I had the harness out I had the injectors cleaned and o-rings replaced.
Disconnect the 02 sensors and see how it runs. If no difference then check the engine wiring harness by the EGR pipe where it's often damaged by heat.
+1 -Agree
- Thread starter
- #25
I found corrosion in the sockets - I cleaned with contact cleaner - going to check resistance again now that I know more what to look for.
I'll take a look at that harness near the EGR pipe
Any good posts or youtube on removing these o2 sensors? Mine looks hard to get into with the ?heat plates? in the way.
I did replace the throttle position sensor - didn't seem to change much of anything
I used a 1/4" ratchet as it was smaller but was a pain to get to and get leverage. You could also try some ratcheting combo wrenches.
- Thread starter
- #27
It's odd - because when it happens, it's about 3-5 minutes after I start the truck - and at times, it doesn't happen at all.
After I changed the throttle position sensor, I drove it for a good 30 minutes without the bogging. I parked it, and then the next morning, started her up and started driving - within 1/4 mile, the bogging started again :-/
After I changed the throttle position sensor, I drove it for a good 30 minutes without the bogging. I parked it, and then the next morning, started her up and started driving - within 1/4 mile, the bogging started again :-/
- Thread starter
- #28
So, I measured the resistance on both O2 sensors and both tested out at 5 ohms. I then turned on the ignition and tested both O2 plugs, both have full voltage.
I didn't tear the protective layer from the harness, but nothing seems out of place or damaged.
Drove the truck around yesterday with the O2 sensors unplugged and it was slightly sluggish... Tried it again this morning, and it bogged down again about 5 minutes after I started it.
I'm going to tune the new throttle position sensor next just to make sure that's not the problem.
I didn't tear the protective layer from the harness, but nothing seems out of place or damaged.
Drove the truck around yesterday with the O2 sensors unplugged and it was slightly sluggish... Tried it again this morning, and it bogged down again about 5 minutes after I started it.
I'm going to tune the new throttle position sensor next just to make sure that's not the problem.
So both times you drove it with the O2 sensors unplugged, how does it run with them plugged in?
Glad the harness looks okay, try moving the harness around with the car idling.
Glad the harness looks okay, try moving the harness around with the car idling.
That doesn't look great to me.
- Thread starter
- #31
Thanks, I'll dig into it
- Thread starter
- #32
It bogs down with them connected. I've moved the harness around...
Have you checked fuel pressure?
- Thread starter
- #34
Haven't got a tool for that, so, no I haven't
alia176
SILVER Star
I didn't read the whole thing but if this is happening when the engine is getting revved to higher rpms, I wonder if the engine ECU harness is acting up by the EGR pipe where it's known to melt wire insulation? Usually this issue happens when the driver is climbing a steep hill in 4hi or 4low due to the engine rotating a little under load.
Checking the fuel pressure is a good idea. I recently had intermittent hesitation and loss of power. Also had low idle and trouble starting. Finally checked the fuel pump and the hose clamps were too loose and the short fuel hose had shifted, allowing it to leak back into the talk, preventing pressure from building up in the line. Re-positioned the hose and tightened the clamps and was amazed at the difference, felt like a new truck!
