1999 Ranger 2.5 4cyl pings???

When I started the cold engine, after resetting the computer for the O2 sensor replacement, it ran perfect cold without any hesitation. The next morning I started it cold again, and it hesitated until up to normal operating temp. (which is what it did prior to O2 sensor replacement) I know that the O2 sensors aren't a part of the equation because it is still in open loop until normal operating temp anyway and the computer was probably running some basic pre-programmed calculations until it had a chance to re-learn......BUT does the fact that it ran perfect after a reset mean that there probably isn't a carbon build up problem but rather some sensor misreporting info to the computer?

As of today it is pinging pretty much more than ever! Here is what it does...

it runs somewhat rough (not bad) but definately not like when I bought it at 32k miles. After it is warm (closed loop) it pings on inclines, under load and sometimes just going down the freeway! There is distinct power loss now and sometimes the engine stumbles and stalls while going down the road (not often) but the engine always starts right back up after a second or two!

I had to replace the MAF about 7500 miles ago because it wen't bad (shop ripped me off!) I have since cleaned the MAF again, replaced both O2 sensors and run 2 cans of B12 in tank, all to no avail! I have called 2 local Ford dealers and spoke to 2 different service bozos. These guys just tried to blame it on the local gas, said they couldn't troubleshoot because of no "check engine light" and tried to rush me off the phone!

Is it possible the MAF wen't bad again? And cleaning it is not helping because it is malfunctioning? If I disconnect it and the engine runs better, does that mean it needs to be replaced?

HELP HELP HELP

snipped-for-privacy@yahoo.com wrote in news:1115915558.011313.177310 @g14g2000cwa.googlegroups.com:

how many miles now and have the plugs,wires, fuelfilter? been changed. KB

56k miles, plugs and wires aren't scheduled to change until 100k. fuel filter was changed about 6k ago...

snipped-for-privacy@yahoo.com wrote in news:1115948156.259238.139390 @f14g2000cwb.googlegroups.com:

without a real time scanner I couldn`t really do a good guess even. KB

On Thu, 12 May 2005 09:32:38 -0700, mike2711 rearranged some electrons to form:

I doubt the engine will run better if you disconnect the MAF. Have you tried some different gas?

If anyone is interested... I took it to a shop for a diagnostic, and all sensors checked out fine. Mechanic says plugs, wires need to be repaced, and fuel injectors need to be cleaned. He says there is evidence of substantial carbon build up. After he does all this, it runs much, much better. It no longer hesitates when cold and it runs much smoother. BUT it pinged all the way home! After talking to the mechanic, he suspects it may be the coolant temp sensor that is misreporting. I went to Napa and picked one up for $20. I replaced the old one and drove it for 30 minutes. Very little pinging, if any, and if I did hear any, it was barely audible. ;good; So I think we found the culprit. My wife had a 2001 Jetta and we had to change the coolant temp sensor twice in that car. Thanks to everyone for all their help!

A good tech with a scan tool should have looked at the coolant temp, although I've not fought a pinging problem for the temp sensor, it does cause hard starts. Now for my advice. Go to Ford and buy a coolant temp sensor. put it away until you have this problem again. I put two NAPA sensors in my ford truck and one in my Mom's Taurus. The truck lasted a year each. The Taurus about 6 months. I learned. Napa's sensor is a plastic tip, Ford is a brass tip. Also, Stick with Ford EGR valves!

Steve

Thanks Steve!