Hello everyone. So far I have changed all coil packs. Spark plugs. Throttle body. And accelerator pedal. And it still won't go over 5mph. It's at the mechanic shop and they don't know. They unplugged the o2 sensor and said there was no change. But about a year ago when I passed a vehicle it smelled like rotten eggs. And it also threw a code for a camshaft sensor. But the mechanic said it couldn't be that because my vehicle doesn't run hot? Please help
NEED HELP 2003 TB 4.2. Wont go over 5mph
- Thread starter Joshj517
- Start date
What codes are you showing? It's hard to diagnosis without any codes. What is the history of this vehicle? Has the fuel filter been changed recently?
Sparky
Member
- Dec 4, 2011
- 12,927
Mooseman
Moderator
Chickenhawk
Member
- Dec 6, 2011
- 783
Stop throwing parts at it that have nothing to do with your problem unless they are throwing their own codes. When a vehicle cannot go over 5 mph and there are no codes, there are only two very common causes: transmission issues and a plugged cat converter. Get a new mechanic and get your cat PROPERLY checked with a backpressure test, not just a "well, it can't be the cat because it's not overheating." The reason it is not overheating is simple ... it's not flowing any exhaust. Temperature checks and IR thermo checks help identify PARTIALLY plugged cats, but they are most useful with inefficient cats. Yours is plugged completely.
Replace the cat and find out how it became plugged, or you will be doing it again in six months. Did you ever drive it with a flashing check engine light? What is the position of the needle on your coolant temperature gauge? Answers to these questions are important.
If your backpressure test is fine (0 PSI at idle, and no more than 1 PSI at 2500 RPM) then look at the transmission. When parts fail in the transmission, they can mimic fuel, intake or exhaust problems. But always go with the cheapest and easiest to diagnose first. This is why my money's on your cat needs replacing.
Replace the cat and find out how it became plugged, or you will be doing it again in six months. Did you ever drive it with a flashing check engine light? What is the position of the needle on your coolant temperature gauge? Answers to these questions are important.
If your backpressure test is fine (0 PSI at idle, and no more than 1 PSI at 2500 RPM) then look at the transmission. When parts fail in the transmission, they can mimic fuel, intake or exhaust problems. But always go with the cheapest and easiest to diagnose first. This is why my money's on your cat needs replacing.
Yes when I started driving the check engine wind flash. My temp never gets hot unless it's really hot outside and it's just idling. Other than that around 180-210
I was doing what the mechanic said was the problem
Your temp gauge should never be anything other than almost 12oclock 210 degrees, CONSISTENTLY, except on cold engine start up.
If its reading below that, than you have already found 1 of your problems, thermostat.
Also, there is an easy way to tell if you have a plugged CAT, remove the O2 sensor, and try driving it. If you go over 5 MPH, than you may have found your problem.
If its reading below that, than you have already found 1 of your problems, thermostat.
Also, there is an easy way to tell if you have a plugged CAT, remove the O2 sensor, and try driving it. If you go over 5 MPH, than you may have found your problem.
Chickenhawk
Member
- Dec 6, 2011
- 783
It's a chain. Misfires cause raw fuel in the cat. (This is why the check engine flashes, and the owners manual says to pull over immediately.) Low coolant temps cause rich mixtures in the long term, which plugs cats. Step one is find and fix the cause of the misfires. (Hopefully you have done that.) Step two is to replace the thermostat and the coolant temp sensor. Step three is to check the cat and replace it. (Trust me; it's toast.) All will be well.
Someone in there, you might want a new mechanic.
Someone in there, you might want a new mechanic.
