Bucking while driving when hot

ROBCHILDS8

MEMBER
2005 FORD ESCAPE
3.0L
6 CYL
4WD
AUTOMATIC
220,000 MILES

Vehicle started bucking while driving, but not until the vehicle is hot. It runs fine for about 10-15 miles, then when the engine heats up, it will start bucking. Every time the vehicle bucks, I can hear what sounds like a relay clicking under the dashboard. There is no check engine light on, and all fluids are full. Any help pointing me in the right direction to repair this would be greatly appreciated. I don’t have the money to pay a mechanic at the moment, but I have tools, and enough money to buy parts. Thanks!

Thursday, June 16th, 2022 AT 1:47 PM

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
50,162 POSTS

Good to hear, let's fix it. The relay you hear clicking can be a clue to the problem, but I would like to scan for codes because an engine misfire can cause the problem as well. Are the spark plugs etc., fairly new? I have seen ignition coils go out as well. Anyway, sometimes a code will not be set if the problem has just started. Let's follow these guides and I have included the SJB (smart junction box - BCM) that I think might be the problem if everything checks out. These go out a lot.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

This guide can tell if the SJB is going bad.

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Images (Click to make bigger)

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Friday, June 17th, 2022 AT 11:55 AM

ROBCHILDS8

MEMBER
2 POSTS

I initially thought it might be the coils as well, but I ran a code scan on it a couple of months ago when the problem first started, and the only thing that was in there was an old code for a transmission range sensor. I did notice something new yesterday, right after I posted my question on here. Every time it lunges, and I hear that relay clicking sound, the gear indicator quickly switches from Drive to Reverse, then it switches back to Drive right away. I tried to look for this symptom before, but I think I just never caught it as my attention was on the road and not the gear indicator. I’ll run a code scan on it again tomorrow, but now that I noticed the gear selection switching back and forth, I am back to thinking it might be that transmission range sensor. Am I on the right track? Thank you very much!

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Friday, June 17th, 2022 AT 4:47 PM

KEN L