I have a 99tl that was throwing the low egr flow/multiple misfires in multiple cylinders. Following the excwllent advice in this forum, I performed the EGR port cleaning. This had been performed twice before, but when I got to the EGR port, it was completely blocked I cleaned out the port, the intake manifold. Still had the codes and the rough idle. I then replaced the spak plugs and the EGR valve itself. I am about to begin swapping out the coil to see if I have a bad one.

I have two questions. Is there anything else I should be looking at, and is there a way to test the coils, like perfomring a simple resistance test similar to the old-style coils with a distributor? Thanks in advance.

 

any misfire codes?

 

some have disconnected the wire to a coil, but might be such a slight differance in idle they didnt spot the bad coil and kept misdiagnosing until a new coil was tried on each cyl
remember- after each test the ECU must be reset- use the clock fuse

without codes we are totally guessing
with codes we can speculate~
See your local parts store for a free code reading

 

what plugs did you install.. ngk iridium or platinum?
or something else?

 

I am going to get the codes rechecked over lunch today and I will let you know what comes up! Have you ever had to clean the EGR port a second time?

 

did you reset the ECU after the cleaning?

 

It was still sluggish at idle, but drove about 20 miles before the engine cel returned. It is a lot smoother then before, but obviously still has a few issues.

 

clean the round air plate inside the TB- use carb cleaner
get both sides and edges

and you reset ecu by pulling the CLOCK fuse on passenger end of dash for a minute?
thats the `secret backup power for ecu`--
remember to reset it each time you make a change during diagnostics

multi cyl misfire codes is often 1 bad coil-
and it might even be one of the cyls the codes give!!,,not guaranteed but worth starting with them~

 

how did the old plugs look? pull a few plugs now and see what color is happening

the egr ports on the 6 port models from 00+ needs cleaning every 75kmiles
I can imagine the single port 99 is even faster and it has a smooth liner in the flow- which may even limit the space for crud
Ethanol e10 gas is a major cause of the problem

must remove intake manifold- soak thru egr port an main chamber with carb cleaner or solvent tank and wire coat hanger to poke the stuff thru and out
Follow that up with the water rinse and finally use compressed air thru the passageways if possible- at least a hair dryer to get water out
a leaf blower might work at the throat of the manifold--just a thought

 

Thank you for all the good advice and information in these forums. You have helped me with many things long before I decided to join.

In reverse order. I did the EGR port and intake manifold cleaning following the excellent directions in the DIY and in the Honda bulliten.

I replaced the plugs with the NGX irridium IX also per the great advice on here, I even had an argument with a parts shop that didn't carry that plug over why I didn't need it. Another point for the Zine and the excellent people who support it.

so...

I went to get the codes checked over lunch. After my 25 mile drive after resetting the codes, I had a p0300, p0302,p0303,p0304, and p1399

I bought a coil, but I decided to disconnect the the cable to see if I'd get lucky and I did! The first one I disconnected made no difference in the rough idling. I pulled three more and each one made a significant difference. I repaced the coil in the first one and then I disconnected it to ensure that i could tell the difference with a new coil pack installed. It was huge!

So for my victory celebration, I seafoamed it. The poor guy at Autozone had to help run the gas as I filled his parking lot with smoke! We have a small four-lane isolated loop so I ran up and down that like a high school kid out cruising. I don't think I offended anyone, except maybe that poor guy behind me at the light in the camero convertible!

I know I already said (typed) it , but thank you again. She is running like a rocket and the seafoam hasn't even settled in yet!

 

you reset the ECU? make sure you do that~

 

what did the parts store try to sell you for plugs?

 

Yes, I reset the ecu after each round. I had to reset it one last time after using the seafoam. I went cruising and put about 30 miles on it using the manual shift so i could vary the rpms. No cel since and I don't remember it ever having this much power.

They were pushing the autolite xp irridium and the bosch platinum

 

both those are NOT approved plugs for the TL!!
Never use bosch as they are proven on TL cars to fail after 6 months
Denso OR NGK only!!!!- ngk preferred for lower price and longer plug life

dont have to reset ecu after seafoam but it wont hurt the car to do so
Who knows what crud has done to the settings

Did you run a can thru just under half tank of gas? (8 gallons to 16 oz can)
that gets the injectors,fuel rails etc, and does a secondary cleaning of intake valves and piston tops

Spray clean the TB air plate if not done yet

when you do the oil cleaning method with some drive- the old oil comes out blacker than anything you have imagined--engine runs smoother-faster- leaps tall buildings...

 

used the NGK based on recommendations from this group

I did reset the ecu after seafoam because it did set a code right after running it through

I was just under a quater tank when I ran the seafoam through. and the oil was very black. Yes the enginge has a lot more power as I detailed above. She is running great and I am very grateful.

 

you got a CEL during the blowout drive?
must not have been enough heat in the exhaust or not long enough drive, rpm ....something was off in the process ..
but it will self clear that light after a day or 2 driving--its just crud stuck on the O2 sensor

 

seafoam- 2 oz per gal fuel is cleaning dose
amounts above 2 oz per gal are not doing any more cleaning per seafoam
I suggest 1 can to ~half tank so it gets a longer time to run cleaner at heavy does thru