Stumbling/hesitating, running out of options (1 Viewer)

[arcteryx]

Hi, Have you run a vacuum and compression test ? Mike

On the todo list

 

[weigellj]

I ordered a fuel pump and an Front 02 sensor as nothing I have tried has helped. Will have and update Friday

 

[weigellj]

Well I put the new denso fuel pump in. Starts, idles like normal. Put it in drive and no stumbles at 2k. Starts like it used too and sounds like it did before the issues. Old pump looked fine, and sock was not plugged. Now I have bigger problems as I have a pinhole leak on the return line going into the tank. I am guessing this wasn't leaking before I messed with it as there was no leaks on the shop floor. Guess I get to fab a new return line. Not to shocking with WI rust. Won't know for sure until I take it for a test drive after the return line fix.

UPDATE - Fixed fuel return line. As soon as I backed out of the shop, it did the same thing again, hesitating, stumbling about 20 feet from the shop. Back in now. Fuel pump isn't it.

 

[bigredmachine]

does the misfire happen hot, cold or all the time? have you checked your o2 sensors at the dlc connector and have you checked the harness for the o2 sensors for any corrosion or poor repairs?

i had a similar issue with a misfire and o2 sensors were testing bad, replaced and still had a misfire. i ended up finding poor corroded wire repairs farther up the harness for the o2 sensor where it looked like the harness had been rubbing on the front ds

 

[weigellj]

Well mine appears to be fixed. I replaced the 1st o2 sensor. Old one looked like it came from the bottom of lake michigan. Note I did not clear the computer and I think I should of. It had one slight hesitation when I backed it out of the shop, but nothing like before. I went around the block about 10 minutes. Starting, stopping, hammering on it, with no problems now.

Makes Zero sense to me as if the O2 sensor was bad, it should of tripped the check engine light again as crappy as it was running.

My misfire happened Hot, cold did not matter.

 

[ScottMac]

I had a similar issue years ago and the fuel sock in the gas tank was full of sediment. I had filled up at a station while they were accepting fuel delivery and it stirred up a bunch of crap that went into my tank. I just skimmed thru this thread and didn't see where you checked out this possibility. To get to the tank's fuel sock there is an access panel under the rear seat.

 

[arcteryx]

Sadly, I don't have much to report as I have not worked on it. I did manage to do a compression test and am very pleased with these numbers. I also ordered a OBD1 scanner, hopefully it will help diagnose this. More to come in the next week or so...

1. 175
2. 177
3. 175
4. 173
5. 175
6. 180



 

[arcteryx]

Well, to close this out, I ended up troubleshooting and pinpointed it to #3 or #4 injector, but really thought it was the #3. For various (lame) reasons, I never got around to swapping it so last week I put it in to my mechanic, sure enough it was the #3 injector. Drove it home today for the first time in almost 2 years, felt really good to be behind it again. Frustrating since I just had all of them cleaned/tested 10K miles earlier. The injector was working but the spray pattern was bad, hence the misfire.

Radio didn't work, checked the fuse , it was blown so I replaced it. Works fine.

AC doesn't work either, the compressor pulley is not turning. I need to jumper it to see if it will turn.

While driving home, I pulled off on a gravel construction site to test the lockers, it locked up in 3 seconds, that put a smile on my face.

Thanks again for those that helped, appreciate it.

 

[77mustard40]

Glad it worked out JD

 

[arcteryx]

Glad it worked out JD

Thanks K. Holler if you need help with your new 80.