Mechanics

CHECK ENGINE LIGHT AND SPORATIC ROUGH IDLE.

1994 Ford Ranger • 103,000 miles

I recently was trying to be proactive with a repair and have since experienced multiple problems. I took the truck in and had the lower intake gaskets replaced, I knew they were leaking. When I picked the truck up and drove home, the check engine light came on and the car was idling very rough.
I took the truck back and they said that the Mass Air Flow needed to be replaced, reluctantly I approved the repair and accepted coincidence.
I picked the car up again and while driving home the check engine light came on again, called mechanic and was told perhaps they forgot to reset code.
I took truck back again and said I felt it was still running a bit rough off and on. They said the cleared the check engine light and said the car ran great for them the entire time.
I left the shop and on my way to work today "CHECK ENGINE" again. The truck still feels as though it is surging a bit when I'm at a stop for a few minutes with brake on. Any direction or ideas is GREATLY appreciated.
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Tmitch
October 28, 2013.




If the check engine light is coming on, you need to have the computer scanned so we know where the problem is coming from. Take the vehicle to a nationally recognized parts store and have them scan the computer to see what the codes are. Then, let me know what you find.

I'll do that - it goes off when I turn the truck off and then eventually comes back on. Does the check engine light have to be "on" for them to read the code?

Tiny
Tmitch
Oct 28, 2013.
In most cases, yes it has to be on. However, if there is a hard code stored, usually you can get that with the light off.

The light came back on and I took it by AutoZone, they were not able to hook up the code reader because the truck does not have the plug in for the code machine under the dash. The guy did look under the hood and found a hose that had been torn completely it was a small hose (emmissions) and he thought there was a possibility that this was triggering the check engine light and may have even have thrown a bad code for the Mass Air Flow Sensor which may not have been needed to replace.

I drove back to the mechanic shop and showed him the hose of course he assured me that the Air Flow Sensor was in fact bad and that this hose would not have made a difference (who knows). He hooked up the code machine and it was reading that the oxygen sensors were not functioning properly, one was bad and the other running lean.
I asked if the tube that was broken would possibly alter a true reading on that machine. He replaced the small piece of tubing and told me to drive it for a couple days and see if the check engine light came back on that the tubing may make a difference.

I explained to him about the sporatic surging when I am at a stop light sitting with the brake on. He told me that once the brain (computer) in the car is cleared that it may need to relearn itself and my driving habits and that those symptoms may adjust themselves.

Something new happened last night, the car had been sitting for about an hour and when I started it and went to accelerate it just creeped along and then I heard a clunk under the hood (not like a hard shift) but a strange clunking and then the car picked up speed.

I am not going back to this mechanic - I will return to my old mechanic althought he is not close in proximity, I'll make it work. I guess my question at this point is - does any of what I have been told sound accurate? I've now dropped about $1,000 dollars into my truck and if I don't need to start again with another mechanic I'll wait. Any direction you can offer is appreciated.
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Tiny
Tmitch
Oct 29, 2013.
What he said could be accurate. However, I would start by repairing the vacuum hose. A small leak could cause a lean fuel mixture as well as a rough idle.


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