05 Tahoe. 5.3 vortec. Starts and runs fine until it hits regular operation temperature. Then it runs rough stalls mileage falls off. I changed the MAP. No change. I have a temp sensor but that's a bigger job than checking the MAF sensor. No check engine light lately but came on a while back but went back off. I think you can disconnect the MAF if it runs better, you've found the problem, right? If its not the MAF. ILL change the temp sensor and don't know where to go after that
Need advice quickly please.
- Thread starter RonnieB2
- Start date
Everytime I blew a head gasket I changed my plugs because it's easier.
Run your diagnostic tree. Pull the codes and troubleshoot from there.
Has 8 new AC Delco plugs and AC Delco Wires....
There ya go! How about oxygen sensors you have any of those?
I thought bad Coil but the misfires are random, so I know the coils are all bad, or its not that.. I'm gonna go inspect the MAF, I bet it needs cleaning anyway. My Camry did this and it was the temperature sensor. but this is a Chevy...IT just amazes me that it runs so smooth until it hits operating temp. then goes to hell
O2 sensors would be next I guess...I'm trying to get the easy stuff out of the way first...O2 sensors would be after the Temp Sensor..So I'm checking the MAF now, if its not that, replacing the Temp sensor, if its not that on to the O2 sensors. Cad Converter should be good because it has plenty of power
Laughing Grass
Well-Known Member
calmag... the answer is always calmag.
Awwww, hell that I got plenty of...LOL....Its pissing me off..I can run quick errands but if it warms up, I'm screwed. I was told if I unplug the MAF and it clears up, then I've found the problem...Fuel pressure is over 60, so I know its getting fuel. crank sensor reading is good, cam sensor is good, so something is dumping too much gas after it warms up...Or something is causing the injectors to dump too much gas...Temp sensor could be sending a false signal or the MAF is screwed up..There are no vacuum leaks either, and I cleaned the throttle body
tyler.durden
Well-Known Member
I'd take it to a mechanic, they are really good with this stuff. Then sit back and get high, they'll call you when it's ready. You're welcome.
Let's not forget checking on your crank position sensor.
Anyway I would start by pulling the codes and following Chevy's diagnostic tree.
Laughing Grass
Well-Known Member
That sucks, sorry I can only add smart ass comments to this thread.
Wake_n_bake73
Member
Bank 1 o2 sensor pre cat ??
its been checked, so has the cam sensor...My mechanic spent 5 days on it, didn't charge me a red cent...but he had to stop chasing it because his work was really backed up...I'm blessed to have a great mechanic, but everyone takes their cars to him because he's also the best transmission guy in the area...While he was chasing the problem I had him put a new water pump on, thermostat, 8 plugs and 8 wires. plus all the time he spent trying to find this problem. and he added a can of freon...My bill was 248 dollars...I felt so guilty that I gave him 350 because of the 5 days work he lost or that backed up on him...He really is a great guy
If its not the MAF or the Temp sensor, thats my next stop. These are the easiest to get to, so I may as well knock them out while I can
What codes did your mechanic pull?
Doesn't suck for me, matter of fact I find it quite enjoyable. Please keep up your witty repartee
I don't know the numbers but he was getting random misfires on all 8 cylinders ....I forgot to tell him the check engine light came on a few weeks earlier and went back off, I'm not sure if he could go back and look at the history or not...I'm not a mechanic by a long shot...If I have directions I can fix something as long as its something like this or an alternator because its pretty simple stuff...I'm headed outside to unplug this MAF sensor and see what happens...I may zip up to the parts store and get some cleaner too to clean the MAF or just buy another. I only use AC Delco on my vehicles ...I won't wash them but I service my cars religiously ...Thats why this is bugging me so bad. I always have my cars serviced
J232
Well-Known Member
If you unplug the maf it will default to another or use some set parameters. So if it improves, the maf is faulty. Same goes with any fuel calculation sensors. Sounds more like a o2 sensor if it’s good when first started. Can try unplugging the front o2 sensors, I would be checking stored codes for direction first.
Look at your receipt the codes should be written on there and then google them.