04-17-2022, 10:45 AM
(This post was last modified: 04-17-2022, 10:55 AM by Zerva5.
Edit Reason: Missed a few works
)
Hello! I've been trying to diagnose this annoying issue on and off for a few months now. The main symptom is at low throttle the engine seems to stumble and recover, stumble then recover, which results in the car jerking forward every time it recovers. I would say it repeats this stumble recover cycle repeats a few times a second.
At first I thought it was EGR related. It passes the stall test however during the live test the EGR valve wasn't moving. I also saw that the idle was very smooth and there was no stumbling. After doing some research I concluded that my sidekick was one of the ones in 1994 where the wheels needed to be spinning for the EGR to engage. I didn't have access to a jack at the time but I tried lightly revving it in neutral while stopped as well as while moving and found that it wouldn't stumble when I wasn't moving but would stumble when I was coasting.
Today I was able to use my buddies jack and did the live test which it passed. Interestingly even with the wheels spinning I wasn't able to make it stumble revving it in neutral. I was also thinking it may have been ECU related and that the VSV was opening and closing and making it stumble. I didn't hear any clicking from the VSV or ISC solenoid so I ruled that out for now.
My buddy is buying a used engine that has a MAF sensor I'm going to throw on and see how it goes. The engine also sounds like it is misfiring a bit at idle. Nothing too bad however.
Things I've checked/done:
VSV: Blowing through it and with 12v
EGR Main: cleaned it top to bottom
EGR Diaphragm: Checked for a clog, there was one, unclogged it, didn't change anything
TPS: Replaced with a used one and calibrated it, no difference
Spark plugs: Replaced
Air Filter: Very clean
MAF: Its clean, didn't check anything else
What I'm planning to do:
Distributor Cap
Distributor Rotor
Plug Wires
Fuel Filter
Check for vacuum leaks
Change timing belt & water pump
I'm not really sure where to go from here, I have an entire used intake I was thinking of doing a deep clean on and swapping in but wonder if you have any other ideas.
Thanks!
At first I thought it was EGR related. It passes the stall test however during the live test the EGR valve wasn't moving. I also saw that the idle was very smooth and there was no stumbling. After doing some research I concluded that my sidekick was one of the ones in 1994 where the wheels needed to be spinning for the EGR to engage. I didn't have access to a jack at the time but I tried lightly revving it in neutral while stopped as well as while moving and found that it wouldn't stumble when I wasn't moving but would stumble when I was coasting.
Today I was able to use my buddies jack and did the live test which it passed. Interestingly even with the wheels spinning I wasn't able to make it stumble revving it in neutral. I was also thinking it may have been ECU related and that the VSV was opening and closing and making it stumble. I didn't hear any clicking from the VSV or ISC solenoid so I ruled that out for now.
My buddy is buying a used engine that has a MAF sensor I'm going to throw on and see how it goes. The engine also sounds like it is misfiring a bit at idle. Nothing too bad however.
Things I've checked/done:
VSV: Blowing through it and with 12v
EGR Main: cleaned it top to bottom
EGR Diaphragm: Checked for a clog, there was one, unclogged it, didn't change anything
TPS: Replaced with a used one and calibrated it, no difference
Spark plugs: Replaced
Air Filter: Very clean
MAF: Its clean, didn't check anything else
What I'm planning to do:
Distributor Cap
Distributor Rotor
Plug Wires
Fuel Filter
Check for vacuum leaks
Change timing belt & water pump
I'm not really sure where to go from here, I have an entire used intake I was thinking of doing a deep clean on and swapping in but wonder if you have any other ideas.
Thanks!