Crawford93

98 gs400


So I recently purchased this car, first thing I did was clean the TB and MAF, as I noticed it was a bit it hesitant when applying throttle.

Also changed both OCV as it showed code for that. Replaced all the vaccum lines from going to the stock intake, and broke one on the nipples. Without realizing it. Tried repairing the intake box, was unable to. Decided to buy a cold air Intake because the stock replacements were 400+. So after the replacing and cleaning the car will crank and start (if l floor it) but dies quickly after letting off the throttle. And is misfiring. I've checked all vac lines and connection as well as harness connections. Everything seems to be connected, just at a complete loss.

please note the car ran before the TB and Maf cleaning, but now I can't get it to stay running unless I'm on the gas. Replaced the spark plugs (after the cleaning), MAF.

I can do the little things cars but am no where near a mechanic. Looking for a little help with diag before I ship it to Lexus

TrueGS300

I think all you need to do is reset the computer. It doesn't know how to run now that the throttle is cleaned and it had learned its position over the years. Just disconnect both battery cables and touch them together. Use a screwdriver or something to make contact for a good 15-20 seconds. Then reconnect and fire it up. Hopefully it runs good.

Crawford93

I mean I did the cleaning and such with the negative terminal disconnected, wouldnt that have been enough to reset computer?

TrueGS300

Sometimes no. The ECU holds onto memory as best it can. Sometimes you have to force clear it by actually touching positive to negative and wipe it clean. Worth a try at least.

Crawford93

Tried that this morning and it started and died within about 5 seconds. But I didnt have to push in the throttle when I turned the key.

Now if I can get it started and keep it running by holding the throttle does that rule out the fuel pump?

kevin3344

You mentioned you just purchased the car how many miles? Spray some starter fluid in the intake if it runs for a bit without giving it gas it's probably low fuel pressure. What were the codes?

Crawford93

It's got 150k

I was getting misfire codes but I changed the fuel filter and it's not misfiring anymore. Only code I get now is maf and the maf temp sensor. I replaced the maf but still shows the code.

Still wont stay running. The only way I can keep it running is if I unplug the maf.

lexo98

iTrader: (2)

On my GS3 anytime I disconnect the battery I have idle issues till it relearns again. I have to give it throttle for a few minutes before it idles on its own.

Crawford93

Lexo that worked.

Anyone know if the check light for the maf will turn off from my cold air intake if I drive it around for awhile? Need to get plates for this thing and I gotta pass smog

TrueGS300

If you clear codes and codes come back, then they won't go away. Things have to fail checks before engine codes set. There is a problem with the MAF or the install of the CAI.

lexo98

iTrader: (2)

I guess it depends what state your in and if you have exemption stickers but here in Cali they give you a hard time with cold air intakes.